Abstract

A class of chalcogenide alloy materials that shows significant changes in optical properties upon an amorphous-to-crystalline phase transition has lead to development of large data capacities in modern optical data storage. Among chalcogenide phase-change materials, Ge2Sb2Te5 (GST) is most widely used because of its reliability. We use a pair of femtosecond light pulses to demonstrate the ultrafast optical manipulation of atomic arrangements from tetrahedral (amorphous) to octahedral (crystalline) Ge-coordination in GST superlattices. Depending on the parameters of the second pump-pulse, ultrafast nonthermal phase-change occurred within only few-cycles (≈1 picosecond) of the coherent motion corresponding to a GeTe4 local vibration. Using the ultrafast switch in chalcogenide alloy memory could lead to a major paradigm shift in memory devices beyond the current generation of silicon-based flash-memory.

© 2011 OSA

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  1. M. H. Cohen, H. Fritzsche, and S. R. Ovshinsky, “Simple band model for amorphous semiconducting alloys,” Phys. Rev. Lett. 22(20), 1065–1068 (1969).
    [CrossRef]
  2. S. R. Ovshinsky, “Reversible electrical switching phenomena in disordered structures,” Phys. Rev. Lett. 21(20), 1450–1453 (1968).
    [CrossRef]
  3. N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, “Rapid phase transitions of GeTe-Sb2Te3,” J. Appl. Phys. 69(5), 2849–2856 (1991).
    [CrossRef]
  4. M. Wuttig and N. Yamada, “Phase-change materials for rewriteable data storage,” Nat. Mater. 6(11), 824–832 (2007).
    [CrossRef] [PubMed]
  5. D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
    [CrossRef] [PubMed]
  6. J. Hegedüs and S. R. Elliott, “Microscopic origin of the fast crystallization ability of Ge-Sb-Te phase-change memory materials,” Nat. Mater. 7(5), 399–405 (2008).
    [CrossRef] [PubMed]
  7. B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
    [CrossRef]
  8. A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
    [CrossRef] [PubMed]
  9. W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
    [CrossRef]
  10. J. Akola and R. O. Jones, “Structural phase transitions on the nanoscale: The crucial pattern in the phase-change materials Ge2Sb2Te5 and GeTe,” Phys. Rev. B 76(23), 235201 (2007).
    [CrossRef]
  11. T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
    [CrossRef]
  12. S. Hunsche, K. Wienecke, T. Dekorsy, and H. Kurz, “Impulsive softening of coherent phonons in tellurium,” Phys. Rev. Lett. 75(9), 1815–1818 (1995).
    [CrossRef] [PubMed]
  13. A. Cavalleri, T. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, “Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale,” Phys. Rev. B 70(16), 161102 (2004).
    [CrossRef]
  14. L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
    [CrossRef] [PubMed]
  15. M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
    [CrossRef]
  16. M. Hase, Y. Miyamoto, and J. Tominaga, “Ultrafast dephasing of coherent optical phonons in atomically controlled GeTe/Sb2Te3 superlattices,” Phys. Rev. B 79(17), 174112 (2009).
    [CrossRef]
  17. T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
    [CrossRef]
  18. J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
    [CrossRef]
  19. J. Tominaga, R. Simpson, P. Fons, and A. V. Kolobov, “Phase change meta-material and device characteristics,” presented at the European Symposium on Phase Change and Ovonic Science (E\PCOS 2010), Milan, Italy, 6–7 Sept. 2010. http://www.epcos.org/library/library2010.htm
  20. J. M. Combes, A. Grossmann, and Ph. Tchamitchian, eds., Proceedings of the International Conference on Wavelet: time-frequency methods and phase space (Springer-Verlag, Berlin, 1989).
  21. K. S. Andrikopoulos, S. N. Yannopoulos, A. V. Kolobov, P. Fons, and J. Tominaga, “Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials,” J. Phys. Chem. Solids 68(5-6), 1074–1078 (2007).
    [CrossRef]
  22. J. Akola and R. O. Jones, “Density functional study of amorphous, liquid and crystalline Ge2Sb2Te5: Homopolar bonds and/or AB alternation?” J. Phys. Condens. Matter 20(46), 465103 (2008).
    [CrossRef] [PubMed]
  23. M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
    [CrossRef]
  24. M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and S. Hishita, “Dephasing of coherent phonons by lattice defects in bismuth films,” Appl. Phys. Lett. 76(10), 1258–1260 (2000).
    [CrossRef]
  25. T. Dekorsy, W. A. Kütt, T. Pfeifer, and H. Kurz, “Coherent control of LO phonon dynamics in opaque semiconductors by femtosecond laser pulses,” Europhys. Lett. 23(3), 223–228 (1993).
    [CrossRef]
  26. M. Hase, M. Kitajima, S.-I. Nakashima, and K. Mizoguchi, “Dynamics of coherent anharmonic phonons in bismuth using high density photoexcitation,” Phys. Rev. Lett. 88(6), 067401 (2002).
    [CrossRef] [PubMed]
  27. L. Huang, J. P. Callan, E. N. Glezer, and E. Mazur, “GaAs under intense ultrafast excitation: Response of the dielectric function,” Phys. Rev. Lett. 80(1), 185–188 (1998).
    [CrossRef]
  28. M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
    [CrossRef] [PubMed]
  29. A. H. Zewail, “Femtochemistry: Atomic-scale dynamics of the chemical bond,” J. Phys. Chem. A 104(24), 5660–5694 (2000).
    [CrossRef]
  30. J. Siegel, A. Schropp, J. Solis, C. N. Afonso, and M. Wuttig, “Rewritable phase-change optical recording in Ge2Sb2Te5 films induced by picosecond laser pulses,” Appl. Phys. Lett. 84(13), 2250–2252 (2004).
    [CrossRef]
  31. M. H. R. Lankhorst, B. W. S. M. M. Ketelaars, and R. A. M. Wolters, “Low-cost and nanoscale non-volatile memory concept for future silicon chips,” Nat. Mater. 4(4), 347–352 (2005).
    [CrossRef] [PubMed]
  32. G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
    [CrossRef] [PubMed]

2009 (2)

M. Hase, Y. Miyamoto, and J. Tominaga, “Ultrafast dephasing of coherent optical phonons in atomically controlled GeTe/Sb2Te3 superlattices,” Phys. Rev. B 79(17), 174112 (2009).
[CrossRef]

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

2008 (4)

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

J. Akola and R. O. Jones, “Density functional study of amorphous, liquid and crystalline Ge2Sb2Te5: Homopolar bonds and/or AB alternation?” J. Phys. Condens. Matter 20(46), 465103 (2008).
[CrossRef] [PubMed]

D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
[CrossRef] [PubMed]

J. Hegedüs and S. R. Elliott, “Microscopic origin of the fast crystallization ability of Ge-Sb-Te phase-change memory materials,” Nat. Mater. 7(5), 399–405 (2008).
[CrossRef] [PubMed]

2007 (3)

M. Wuttig and N. Yamada, “Phase-change materials for rewriteable data storage,” Nat. Mater. 6(11), 824–832 (2007).
[CrossRef] [PubMed]

J. Akola and R. O. Jones, “Structural phase transitions on the nanoscale: The crucial pattern in the phase-change materials Ge2Sb2Te5 and GeTe,” Phys. Rev. B 76(23), 235201 (2007).
[CrossRef]

K. S. Andrikopoulos, S. N. Yannopoulos, A. V. Kolobov, P. Fons, and J. Tominaga, “Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials,” J. Phys. Chem. Solids 68(5-6), 1074–1078 (2007).
[CrossRef]

2006 (3)

W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
[CrossRef]

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

2005 (3)

B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
[CrossRef]

M. H. R. Lankhorst, B. W. S. M. M. Ketelaars, and R. A. M. Wolters, “Low-cost and nanoscale non-volatile memory concept for future silicon chips,” Nat. Mater. 4(4), 347–352 (2005).
[CrossRef] [PubMed]

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

2004 (3)

A. Cavalleri, T. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, “Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale,” Phys. Rev. B 70(16), 161102 (2004).
[CrossRef]

J. Siegel, A. Schropp, J. Solis, C. N. Afonso, and M. Wuttig, “Rewritable phase-change optical recording in Ge2Sb2Te5 films induced by picosecond laser pulses,” Appl. Phys. Lett. 84(13), 2250–2252 (2004).
[CrossRef]

A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
[CrossRef] [PubMed]

2002 (1)

M. Hase, M. Kitajima, S.-I. Nakashima, and K. Mizoguchi, “Dynamics of coherent anharmonic phonons in bismuth using high density photoexcitation,” Phys. Rev. Lett. 88(6), 067401 (2002).
[CrossRef] [PubMed]

2000 (3)

M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and S. Hishita, “Dephasing of coherent phonons by lattice defects in bismuth films,” Appl. Phys. Lett. 76(10), 1258–1260 (2000).
[CrossRef]

A. H. Zewail, “Femtochemistry: Atomic-scale dynamics of the chemical bond,” J. Phys. Chem. A 104(24), 5660–5694 (2000).
[CrossRef]

M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
[CrossRef]

1998 (1)

L. Huang, J. P. Callan, E. N. Glezer, and E. Mazur, “GaAs under intense ultrafast excitation: Response of the dielectric function,” Phys. Rev. Lett. 80(1), 185–188 (1998).
[CrossRef]

1996 (1)

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

1995 (1)

S. Hunsche, K. Wienecke, T. Dekorsy, and H. Kurz, “Impulsive softening of coherent phonons in tellurium,” Phys. Rev. Lett. 75(9), 1815–1818 (1995).
[CrossRef] [PubMed]

1993 (2)

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

T. Dekorsy, W. A. Kütt, T. Pfeifer, and H. Kurz, “Coherent control of LO phonon dynamics in opaque semiconductors by femtosecond laser pulses,” Europhys. Lett. 23(3), 223–228 (1993).
[CrossRef]

1991 (1)

N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, “Rapid phase transitions of GeTe-Sb2Te3,” J. Appl. Phys. 69(5), 2849–2856 (1991).
[CrossRef]

1969 (1)

M. H. Cohen, H. Fritzsche, and S. R. Ovshinsky, “Simple band model for amorphous semiconducting alloys,” Phys. Rev. Lett. 22(20), 1065–1068 (1969).
[CrossRef]

1968 (1)

S. R. Ovshinsky, “Reversible electrical switching phenomena in disordered structures,” Phys. Rev. Lett. 21(20), 1450–1453 (1968).
[CrossRef]

Abelson, J. R.

B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
[CrossRef]

Acioli, L. H.

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

Adachi, S.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Afonso, C. N.

J. Siegel, A. Schropp, J. Solis, C. N. Afonso, and M. Wuttig, “Rewritable phase-change optical recording in Ge2Sb2Te5 films induced by picosecond laser pulses,” Appl. Phys. Lett. 84(13), 2250–2252 (2004).
[CrossRef]

Akahira, N.

N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, “Rapid phase transitions of GeTe-Sb2Te3,” J. Appl. Phys. 69(5), 2849–2856 (1991).
[CrossRef]

Akola, J.

J. Akola and R. O. Jones, “Density functional study of amorphous, liquid and crystalline Ge2Sb2Te5: Homopolar bonds and/or AB alternation?” J. Phys. Condens. Matter 20(46), 465103 (2008).
[CrossRef] [PubMed]

J. Akola and R. O. Jones, “Structural phase transitions on the nanoscale: The crucial pattern in the phase-change materials Ge2Sb2Te5 and GeTe,” Phys. Rev. B 76(23), 235201 (2007).
[CrossRef]

Anappara, A. A.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Andrikopoulos, K. S.

K. S. Andrikopoulos, S. N. Yannopoulos, A. V. Kolobov, P. Fons, and J. Tominaga, “Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials,” J. Phys. Chem. Solids 68(5-6), 1074–1078 (2007).
[CrossRef]

Ankudinov, A. L.

A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
[CrossRef] [PubMed]

Bechevet, B.

M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
[CrossRef]

Berger, H.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

Biasiol, G.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Biermann, S.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

Bishop, S. G.

B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
[CrossRef]

Blügel, S.

W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
[CrossRef]

Bovensiepen, U.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

Callan, J. P.

L. Huang, J. P. Callan, E. N. Glezer, and E. Mazur, “GaAs under intense ultrafast excitation: Response of the dielectric function,” Phys. Rev. Lett. 80(1), 185–188 (1998).
[CrossRef]

Cavalleri, A.

A. Cavalleri, T. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, “Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale,” Phys. Rev. B 70(16), 161102 (2004).
[CrossRef]

Cheng, T. K.

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

Cheong, B.-K.

B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
[CrossRef]

Chollet, M.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Chong, H. H. W.

A. Cavalleri, T. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, “Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale,” Phys. Rev. B 70(16), 161102 (2004).
[CrossRef]

Chong, T. C.

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Ciuti, C.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Cohen, M. H.

M. H. Cohen, H. Fritzsche, and S. R. Ovshinsky, “Simple band model for amorphous semiconducting alloys,” Phys. Rev. Lett. 22(20), 1065–1068 (1969).
[CrossRef]

Cornaglia, P. S.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

De Liberato, S.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Dekorsy, T.

A. Cavalleri, T. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, “Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale,” Phys. Rev. B 70(16), 161102 (2004).
[CrossRef]

M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
[CrossRef]

S. Hunsche, K. Wienecke, T. Dekorsy, and H. Kurz, “Impulsive softening of coherent phonons in tellurium,” Phys. Rev. Lett. 75(9), 1815–1818 (1995).
[CrossRef] [PubMed]

T. Dekorsy, W. A. Kütt, T. Pfeifer, and H. Kurz, “Coherent control of LO phonon dynamics in opaque semiconductors by femtosecond laser pulses,” Europhys. Lett. 23(3), 223–228 (1993).
[CrossRef]

Detemple, R.

W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
[CrossRef]

Dresselhaus, G.

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

Dresselhaus, M. S.

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

Du, A. Y.

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Elliott, S. R.

J. Hegedüs and S. R. Elliott, “Microscopic origin of the fast crystallization ability of Ge-Sb-Te phase-change memory materials,” Nat. Mater. 7(5), 399–405 (2008).
[CrossRef] [PubMed]

Fons, P.

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

K. S. Andrikopoulos, S. N. Yannopoulos, A. V. Kolobov, P. Fons, and J. Tominaga, “Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials,” J. Phys. Chem. Solids 68(5-6), 1074–1078 (2007).
[CrossRef]

A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
[CrossRef] [PubMed]

Först, M.

M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
[CrossRef]

Frenkel, A. I.

A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
[CrossRef] [PubMed]

Fritzsche, H.

M. H. Cohen, H. Fritzsche, and S. R. Ovshinsky, “Simple band model for amorphous semiconducting alloys,” Phys. Rev. Lett. 22(20), 1065–1068 (1969).
[CrossRef]

Fukaya, S.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Georges, A.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

Glezer, E. N.

L. Huang, J. P. Callan, E. N. Glezer, and E. Mazur, “GaAs under intense ultrafast excitation: Response of the dielectric function,” Phys. Rev. Lett. 80(1), 185–188 (1998).
[CrossRef]

Grabowski, B.

D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
[CrossRef] [PubMed]

Guerin, L.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Günter, G.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Hangyo, M.

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

Harima, H.

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

Hase, M.

M. Hase, Y. Miyamoto, and J. Tominaga, “Ultrafast dephasing of coherent optical phonons in atomically controlled GeTe/Sb2Te3 superlattices,” Phys. Rev. B 79(17), 174112 (2009).
[CrossRef]

M. Hase, M. Kitajima, S.-I. Nakashima, and K. Mizoguchi, “Dynamics of coherent anharmonic phonons in bismuth using high density photoexcitation,” Phys. Rev. Lett. 88(6), 067401 (2002).
[CrossRef] [PubMed]

M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and S. Hishita, “Dephasing of coherent phonons by lattice defects in bismuth films,” Appl. Phys. Lett. 76(10), 1258–1260 (2000).
[CrossRef]

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

Hasegawa, T.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Hees, J.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Hegedüs, J.

J. Hegedüs and S. R. Elliott, “Microscopic origin of the fast crystallization ability of Ge-Sb-Te phase-change memory materials,” Nat. Mater. 7(5), 399–405 (2008).
[CrossRef] [PubMed]

Hickel, T.

D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
[CrossRef] [PubMed]

Hishita, S.

M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and S. Hishita, “Dephasing of coherent phonons by lattice defects in bismuth films,” Appl. Phys. Lett. 76(10), 1258–1260 (2000).
[CrossRef]

Huang, L.

L. Huang, J. P. Callan, E. N. Glezer, and E. Mazur, “GaAs under intense ultrafast excitation: Response of the dielectric function,” Phys. Rev. Lett. 80(1), 185–188 (1998).
[CrossRef]

Huber, R.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Hunsche, S.

S. Hunsche, K. Wienecke, T. Dekorsy, and H. Kurz, “Impulsive softening of coherent phonons in tellurium,” Phys. Rev. Lett. 75(9), 1815–1818 (1995).
[CrossRef] [PubMed]

Ippen, E. P.

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

Ishikawa, T.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Ishioka, K.

M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and S. Hishita, “Dephasing of coherent phonons by lattice defects in bismuth films,” Appl. Phys. Lett. 76(10), 1258–1260 (2000).
[CrossRef]

Jones, R. O.

J. Akola and R. O. Jones, “Density functional study of amorphous, liquid and crystalline Ge2Sb2Te5: Homopolar bonds and/or AB alternation?” J. Phys. Condens. Matter 20(46), 465103 (2008).
[CrossRef] [PubMed]

J. Akola and R. O. Jones, “Structural phase transitions on the nanoscale: The crucial pattern in the phase-change materials Ge2Sb2Te5 and GeTe,” Phys. Rev. B 76(23), 235201 (2007).
[CrossRef]

Kang, D.-H.

B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
[CrossRef]

Ketelaars, B. W. S. M. M.

M. H. R. Lankhorst, B. W. S. M. M. Ketelaars, and R. A. M. Wolters, “Low-cost and nanoscale non-volatile memory concept for future silicon chips,” Nat. Mater. 4(4), 347–352 (2005).
[CrossRef] [PubMed]

Kieffer, J. C.

A. Cavalleri, T. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, “Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale,” Phys. Rev. B 70(16), 161102 (2004).
[CrossRef]

Kim, K.-B.

B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
[CrossRef]

Kitajima, M.

M. Hase, M. Kitajima, S.-I. Nakashima, and K. Mizoguchi, “Dynamics of coherent anharmonic phonons in bismuth using high density photoexcitation,” Phys. Rev. Lett. 88(6), 067401 (2002).
[CrossRef] [PubMed]

M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and S. Hishita, “Dephasing of coherent phonons by lattice defects in bismuth films,” Appl. Phys. Lett. 76(10), 1258–1260 (2000).
[CrossRef]

Kolobov, A. V.

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

K. S. Andrikopoulos, S. N. Yannopoulos, A. V. Kolobov, P. Fons, and J. Tominaga, “Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials,” J. Phys. Chem. Solids 68(5-6), 1074–1078 (2007).
[CrossRef]

A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
[CrossRef] [PubMed]

Koshihara, S. Y.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Kurz, H.

M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
[CrossRef]

S. Hunsche, K. Wienecke, T. Dekorsy, and H. Kurz, “Impulsive softening of coherent phonons in tellurium,” Phys. Rev. Lett. 75(9), 1815–1818 (1995).
[CrossRef] [PubMed]

T. Dekorsy, W. A. Kütt, T. Pfeifer, and H. Kurz, “Coherent control of LO phonon dynamics in opaque semiconductors by femtosecond laser pulses,” Europhys. Lett. 23(3), 223–228 (1993).
[CrossRef]

Kütt, W. A.

T. Dekorsy, W. A. Kütt, T. Pfeifer, and H. Kurz, “Coherent control of LO phonon dynamics in opaque semiconductors by femtosecond laser pulses,” Europhys. Lett. 23(3), 223–228 (1993).
[CrossRef]

Lankhorst, M. H. R.

M. H. R. Lankhorst, B. W. S. M. M. Ketelaars, and R. A. M. Wolters, “Low-cost and nanoscale non-volatile memory concept for future silicon chips,” Nat. Mater. 4(4), 347–352 (2005).
[CrossRef] [PubMed]

Laurenzis, M.

M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
[CrossRef]

Lee, B.-S.

B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
[CrossRef]

Lee, H. K.

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

Lee, K.

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Leitenstorfer, A.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Lencer, D.

D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
[CrossRef] [PubMed]

Li, J. M.

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Lisowski, M.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

Loukakos, P. A.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

Matsuda, K.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Mazur, E.

L. Huang, J. P. Callan, E. N. Glezer, and E. Mazur, “GaAs under intense ultrafast excitation: Response of the dielectric function,” Phys. Rev. Lett. 80(1), 185–188 (1998).
[CrossRef]

Miao, X. S.

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Miyamoto, Y.

M. Hase, Y. Miyamoto, and J. Tominaga, “Ultrafast dephasing of coherent optical phonons in atomically controlled GeTe/Sb2Te3 superlattices,” Phys. Rev. B 79(17), 174112 (2009).
[CrossRef]

Mizoguchi, K.

M. Hase, M. Kitajima, S.-I. Nakashima, and K. Mizoguchi, “Dynamics of coherent anharmonic phonons in bismuth using high density photoexcitation,” Phys. Rev. Lett. 88(6), 067401 (2002).
[CrossRef] [PubMed]

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

Nakashima, S.

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

Nakashima, S.-I.

M. Hase, M. Kitajima, S.-I. Nakashima, and K. Mizoguchi, “Dynamics of coherent anharmonic phonons in bismuth using high density photoexcitation,” Phys. Rev. Lett. 88(6), 067401 (2002).
[CrossRef] [PubMed]

Neugebauer, J.

D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
[CrossRef] [PubMed]

Nishiuchi, K.

N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, “Rapid phase transitions of GeTe-Sb2Te3,” J. Appl. Phys. 69(5), 2849–2856 (1991).
[CrossRef]

Ohno, E.

N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, “Rapid phase transitions of GeTe-Sb2Te3,” J. Appl. Phys. 69(5), 2849–2856 (1991).
[CrossRef]

Ota, A.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Ovshinsky, S. R.

M. H. Cohen, H. Fritzsche, and S. R. Ovshinsky, “Simple band model for amorphous semiconducting alloys,” Phys. Rev. Lett. 22(20), 1065–1068 (1969).
[CrossRef]

S. R. Ovshinsky, “Reversible electrical switching phenomena in disordered structures,” Phys. Rev. Lett. 21(20), 1450–1453 (1968).
[CrossRef]

Pamungkas, A.

W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
[CrossRef]

Perfetti, L.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

Pfeifer, T.

T. Dekorsy, W. A. Kütt, T. Pfeifer, and H. Kurz, “Coherent control of LO phonon dynamics in opaque semiconductors by femtosecond laser pulses,” Europhys. Lett. 23(3), 223–228 (1993).
[CrossRef]

Saito, G.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Sakai, K.

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

Salinga, M.

D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
[CrossRef] [PubMed]

Schoenlein, R. W.

A. Cavalleri, T. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, “Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale,” Phys. Rev. B 70(16), 161102 (2004).
[CrossRef]

Schropp, A.

J. Siegel, A. Schropp, J. Solis, C. N. Afonso, and M. Wuttig, “Rewritable phase-change optical recording in Ge2Sb2Te5 films induced by picosecond laser pulses,” Appl. Phys. Lett. 84(13), 2250–2252 (2004).
[CrossRef]

Sell, A.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Shi, L. P.

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Shima, T.

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

Shimoda, H.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Siegel, J.

J. Siegel, A. Schropp, J. Solis, C. N. Afonso, and M. Wuttig, “Rewritable phase-change optical recording in Ge2Sb2Te5 films induced by picosecond laser pulses,” Appl. Phys. Lett. 84(13), 2250–2252 (2004).
[CrossRef]

Solis, J.

J. Siegel, A. Schropp, J. Solis, C. N. Afonso, and M. Wuttig, “Rewritable phase-change optical recording in Ge2Sb2Te5 films induced by picosecond laser pulses,” Appl. Phys. Lett. 84(13), 2250–2252 (2004).
[CrossRef]

Sorba, L.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Steimer, C.

W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
[CrossRef]

Takao, M.

N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, “Rapid phase transitions of GeTe-Sb2Te3,” J. Appl. Phys. 69(5), 2849–2856 (1991).
[CrossRef]

Tan, P. K.

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Tani, M.

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

Tazaki, R.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Tominaga, J.

M. Hase, Y. Miyamoto, and J. Tominaga, “Ultrafast dephasing of coherent optical phonons in atomically controlled GeTe/Sb2Te3 superlattices,” Phys. Rev. B 79(17), 174112 (2009).
[CrossRef]

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

K. S. Andrikopoulos, S. N. Yannopoulos, A. V. Kolobov, P. Fons, and J. Tominaga, “Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials,” J. Phys. Chem. Solids 68(5-6), 1074–1078 (2007).
[CrossRef]

A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
[CrossRef] [PubMed]

Trappe, C.

M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
[CrossRef]

Tredicucci, A.

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Tung, C. H.

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Uchida, N.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Uruga, T.

A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
[CrossRef] [PubMed]

Ushida, K.

M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and S. Hishita, “Dephasing of coherent phonons by lattice defects in bismuth films,” Appl. Phys. Lett. 76(10), 1258–1260 (2000).
[CrossRef]

Vidal, J.

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

Welnic, W.

W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
[CrossRef]

Wienecke, K.

S. Hunsche, K. Wienecke, T. Dekorsy, and H. Kurz, “Impulsive softening of coherent phonons in tellurium,” Phys. Rev. Lett. 75(9), 1815–1818 (1995).
[CrossRef] [PubMed]

Wolf, M.

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

Wolters, R. A. M.

M. H. R. Lankhorst, B. W. S. M. M. Ketelaars, and R. A. M. Wolters, “Low-cost and nanoscale non-volatile memory concept for future silicon chips,” Nat. Mater. 4(4), 347–352 (2005).
[CrossRef] [PubMed]

Wuttig, M.

D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
[CrossRef] [PubMed]

M. Wuttig and N. Yamada, “Phase-change materials for rewriteable data storage,” Nat. Mater. 6(11), 824–832 (2007).
[CrossRef] [PubMed]

W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
[CrossRef]

J. Siegel, A. Schropp, J. Solis, C. N. Afonso, and M. Wuttig, “Rewritable phase-change optical recording in Ge2Sb2Te5 films induced by picosecond laser pulses,” Appl. Phys. Lett. 84(13), 2250–2252 (2004).
[CrossRef]

Yamada, N.

M. Wuttig and N. Yamada, “Phase-change materials for rewriteable data storage,” Nat. Mater. 6(11), 824–832 (2007).
[CrossRef] [PubMed]

N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, “Rapid phase transitions of GeTe-Sb2Te3,” J. Appl. Phys. 69(5), 2849–2856 (1991).
[CrossRef]

Yamochi, H.

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Yannopoulos, S. N.

K. S. Andrikopoulos, S. N. Yannopoulos, A. V. Kolobov, P. Fons, and J. Tominaga, “Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials,” J. Phys. Chem. Solids 68(5-6), 1074–1078 (2007).
[CrossRef]

Zeiger, H. J.

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

Zewail, A. H.

A. H. Zewail, “Femtochemistry: Atomic-scale dynamics of the chemical bond,” J. Phys. Chem. A 104(24), 5660–5694 (2000).
[CrossRef]

Zhao, R.

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

Appl. Phys. Lett. (6)

T. K. Cheng, L. H. Acioli, J. Vidal, H. J. Zeiger, G. Dresselhaus, M. S. Dresselhaus, and E. P. Ippen, “Modulation of a semiconductor-to-semimetal transition at 7 THz via coherent lattice vibrations,” Appl. Phys. Lett. 62(16), 1901–1903 (1993).
[CrossRef]

M. Först, T. Dekorsy, C. Trappe, M. Laurenzis, H. Kurz, and B. Bechevet, “Phase change in Ge2Sb2Te5 films investigated by coherent phonon spectroscopy,” Appl. Phys. Lett. 77(13), 1964–1966 (2000).
[CrossRef]

T. C. Chong, L. P. Shi, R. Zhao, P. K. Tan, J. M. Li, K. Lee, X. S. Miao, A. Y. Du, and C. H. Tung, “Phase change random access memory cell with superlattice-like structure,” Appl. Phys. Lett. 88(12), 122114 (2006).
[CrossRef]

M. Hase, K. Mizoguchi, H. Harima, S. Nakashima, M. Tani, K. Sakai, and M. Hangyo, “Optical control of coherent optical phonons in bismuth films,” Appl. Phys. Lett. 69(17), 2474–2476 (1996).
[CrossRef]

M. Hase, K. Ishioka, M. Kitajima, K. Ushida, and S. Hishita, “Dephasing of coherent phonons by lattice defects in bismuth films,” Appl. Phys. Lett. 76(10), 1258–1260 (2000).
[CrossRef]

J. Siegel, A. Schropp, J. Solis, C. N. Afonso, and M. Wuttig, “Rewritable phase-change optical recording in Ge2Sb2Te5 films induced by picosecond laser pulses,” Appl. Phys. Lett. 84(13), 2250–2252 (2004).
[CrossRef]

Europhys. Lett. (1)

T. Dekorsy, W. A. Kütt, T. Pfeifer, and H. Kurz, “Coherent control of LO phonon dynamics in opaque semiconductors by femtosecond laser pulses,” Europhys. Lett. 23(3), 223–228 (1993).
[CrossRef]

J. Appl. Phys. (2)

N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, “Rapid phase transitions of GeTe-Sb2Te3,” J. Appl. Phys. 69(5), 2849–2856 (1991).
[CrossRef]

B.-S. Lee, J. R. Abelson, S. G. Bishop, D.-H. Kang, B.-K. Cheong, and K.-B. Kim, “Investigation of the optical and electronic properties of Ge2Sb2Te5 phase change material in its amorphous, cubic, and hexagonal phases,” J. Appl. Phys. 97(9), 093509 (2005).
[CrossRef]

J. Phys. Chem. A (1)

A. H. Zewail, “Femtochemistry: Atomic-scale dynamics of the chemical bond,” J. Phys. Chem. A 104(24), 5660–5694 (2000).
[CrossRef]

J. Phys. Chem. Solids (1)

K. S. Andrikopoulos, S. N. Yannopoulos, A. V. Kolobov, P. Fons, and J. Tominaga, “Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials,” J. Phys. Chem. Solids 68(5-6), 1074–1078 (2007).
[CrossRef]

J. Phys. Condens. Matter (1)

J. Akola and R. O. Jones, “Density functional study of amorphous, liquid and crystalline Ge2Sb2Te5: Homopolar bonds and/or AB alternation?” J. Phys. Condens. Matter 20(46), 465103 (2008).
[CrossRef] [PubMed]

Jpn. J. Appl. Phys. (1)

J. Tominaga, P. Fons, A. V. Kolobov, T. Shima, T. C. Chong, R. Zhao, H. K. Lee, and L. P. Shi, “Role of Ge switch in phase transition: Approach using atomically controlled GeTe/Sb2Te3 superlattice,” Jpn. J. Appl. Phys. 47(7), 5763–5766 (2008).
[CrossRef]

Nat. Mater. (6)

M. H. R. Lankhorst, B. W. S. M. M. Ketelaars, and R. A. M. Wolters, “Low-cost and nanoscale non-volatile memory concept for future silicon chips,” Nat. Mater. 4(4), 347–352 (2005).
[CrossRef] [PubMed]

A. V. Kolobov, P. Fons, A. I. Frenkel, A. L. Ankudinov, J. Tominaga, and T. Uruga, “Understanding the phase-change mechanism of rewritable optical media,” Nat. Mater. 3(10), 703–708 (2004).
[CrossRef] [PubMed]

W. Welnic, A. Pamungkas, R. Detemple, C. Steimer, S. Blügel, and M. Wuttig, “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nat. Mater. 5(1), 56–62 (2006).
[CrossRef]

M. Wuttig and N. Yamada, “Phase-change materials for rewriteable data storage,” Nat. Mater. 6(11), 824–832 (2007).
[CrossRef] [PubMed]

D. Lencer, M. Salinga, B. Grabowski, T. Hickel, J. Neugebauer, and M. Wuttig, “A map for phase-change materials,” Nat. Mater. 7(12), 972–977 (2008).
[CrossRef] [PubMed]

J. Hegedüs and S. R. Elliott, “Microscopic origin of the fast crystallization ability of Ge-Sb-Te phase-change memory materials,” Nat. Mater. 7(5), 399–405 (2008).
[CrossRef] [PubMed]

Nature (1)

G. Günter, A. A. Anappara, J. Hees, A. Sell, G. Biasiol, L. Sorba, S. De Liberato, C. Ciuti, A. Tredicucci, A. Leitenstorfer, and R. Huber, “Sub-cycle switch-on of ultrastrong light-matter interaction,” Nature 458(7235), 178–181 (2009).
[CrossRef] [PubMed]

Phys. Rev. B (3)

J. Akola and R. O. Jones, “Structural phase transitions on the nanoscale: The crucial pattern in the phase-change materials Ge2Sb2Te5 and GeTe,” Phys. Rev. B 76(23), 235201 (2007).
[CrossRef]

M. Hase, Y. Miyamoto, and J. Tominaga, “Ultrafast dephasing of coherent optical phonons in atomically controlled GeTe/Sb2Te3 superlattices,” Phys. Rev. B 79(17), 174112 (2009).
[CrossRef]

A. Cavalleri, T. Dekorsy, H. H. W. Chong, J. C. Kieffer, and R. W. Schoenlein, “Evidence for a structurally-driven insulator-to-metal transition in VO2: A view from the ultrafast timescale,” Phys. Rev. B 70(16), 161102 (2004).
[CrossRef]

Phys. Rev. Lett. (6)

L. Perfetti, P. A. Loukakos, M. Lisowski, U. Bovensiepen, H. Berger, S. Biermann, P. S. Cornaglia, A. Georges, and M. Wolf, “Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition,” Phys. Rev. Lett. 97(6), 067402 (2006).
[CrossRef] [PubMed]

S. Hunsche, K. Wienecke, T. Dekorsy, and H. Kurz, “Impulsive softening of coherent phonons in tellurium,” Phys. Rev. Lett. 75(9), 1815–1818 (1995).
[CrossRef] [PubMed]

M. H. Cohen, H. Fritzsche, and S. R. Ovshinsky, “Simple band model for amorphous semiconducting alloys,” Phys. Rev. Lett. 22(20), 1065–1068 (1969).
[CrossRef]

S. R. Ovshinsky, “Reversible electrical switching phenomena in disordered structures,” Phys. Rev. Lett. 21(20), 1450–1453 (1968).
[CrossRef]

M. Hase, M. Kitajima, S.-I. Nakashima, and K. Mizoguchi, “Dynamics of coherent anharmonic phonons in bismuth using high density photoexcitation,” Phys. Rev. Lett. 88(6), 067401 (2002).
[CrossRef] [PubMed]

L. Huang, J. P. Callan, E. N. Glezer, and E. Mazur, “GaAs under intense ultrafast excitation: Response of the dielectric function,” Phys. Rev. Lett. 80(1), 185–188 (1998).
[CrossRef]

Science (1)

M. Chollet, L. Guerin, N. Uchida, S. Fukaya, H. Shimoda, T. Ishikawa, K. Matsuda, T. Hasegawa, A. Ota, H. Yamochi, G. Saito, R. Tazaki, S. Adachi, and S. Y. Koshihara, “Gigantic photoresponse in 1/4-filled-band organic salt (EDO-TTF)2PF6.,” Science 307(5706), 86–89 (2005).
[CrossRef] [PubMed]

Other (2)

J. Tominaga, R. Simpson, P. Fons, and A. V. Kolobov, “Phase change meta-material and device characteristics,” presented at the European Symposium on Phase Change and Ovonic Science (E\PCOS 2010), Milan, Italy, 6–7 Sept. 2010. http://www.epcos.org/library/library2010.htm

J. M. Combes, A. Grossmann, and Ph. Tchamitchian, eds., Proceedings of the International Conference on Wavelet: time-frequency methods and phase space (Springer-Verlag, Berlin, 1989).

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Figures (7)

Fig. 1
Fig. 1

(a) Schematic structure of the Ge2Sb2Te5 superlattice, [(GeTe)2/Sb2Te3]n = 20, fabricated on Si (100) substrate. (b) Optical layout of the Michelson interferometer with a piezo stage to generate the pump-pulse pair. The time interval (Δt) of the two pump-pulses is controlled by moving one arm of the interferometer. BS is a beam splitter.

Fig. 2
Fig. 2

(a) Transient reflectivity changes and (b) their FT spectra observed in the GST superlattice films. The dotted lines in the FT spectra represent the peak positions of A1 mode. The inset of (b) represents the local structural change from GeTe4 to GeTe6 units.

Fig. 3
Fig. 3

(a) The transient reflectivity changes and (b) the corresponding FT spectra observed in the amorphous GST-SL at room temperature. The pump fluence was varied from 47 to 284 µJ/cm2. The dashed arrows in (b) indicate the shift of the peak frequency of the A1 mode, corresponding to the GeTe4 local mode, and that of the pyramidal SbTe3, respectively.

Fig. 4
Fig. 4

(a) Transient reflectivity trace for the amorphous GST-SL film, recorded by the use of the single pump-pulse at 64 µJ/cm2. (b) The experimental schemes around the sample in the case of the single pump. (c) Transient reflectivity trace for the amorphous GST-SL film by the use of the pump-pulse pair of Δt = 276 fs, with the primary pump-pulse fluence F1 = 76 µJ/cm2 and the secondary pump-pulse fluence F2 = 64 µJ/cm2. (d) Same as (b) in the case of the pump-pulse pair excitation.

Fig. 5
Fig. 5

(a) Coherent vibrations in the amorphous phase excited by the pump-pulse pair as the fluence of the second pump-pulse (F2 ) is varied. The primary pump-pulse fluence was fixed at F1 = 76 µJ/cm2, while F2 was tuned from 0 (without second pump) to 64 µJ/cm2. (b) FT spectra from the data in (a). The arrow indicates the shift of the local A1 mode (GeTe4), which is more visible in the variation of the frequency as the function of F2 in (c). The dotted lines in (c) correspond to the frequencies of the local A1 mode (GeTe6) in the crystalline phase (= 3.68 THz) and that (GeTe4) in the amorphous phase (= 3.83 THz), respectively. The solid curve is the guide for the eyes. (d) Coherent vibrations excited by the pump-pulse pair as Δt is varied. (e) FT spectra from the time-domain data in (d). The FT spectrum at Δt = 141 fs is omitted since the intensity is too low to display. The arrow indicates the peak-shift of the local A1 mode (GeTe4), being more visible in (f), which represents the frequency of the local A1 mode as the function of the time interval Δt. The solid curve is the guide for the eyes.

Fig. 6
Fig. 6

Transient frequency of the coherent A1 mode obtained by a wavelet analysis from the time-domain signal with single and pump-pulse pair excitations. The red circles represent the case of the single pump-pulse excitation (F2 = 0 µJ/cm2), while the green circles are for the pump-pulse pair excitation with F2 = 14.5 µJ/cm2, and the blue circles are for those with F2 = 64.0 µJ/cm2.

Fig. 7
Fig. 7

Schematic of the potential energy surface during the pump-pulse pair excitation, together with the local structural change of GST-SL (Top). EA represents the activation energy when the phase change is promoted by thermal (incoherent) process. The position of Ge atoms can be rearranged by the coherent selective excitation of the local vibration, GeTe4, accompanying with surrounding (Sb and Te) atomic rearrangement via an intermediate state (dashed curve). Top: the local structures in the two phases were calculated by the first principle simulation based on density functional theory (DFT). The dashed red circles highlight the local structures of GeTe4 (in the amorphous phase) and GeTe6 (in the crystalline phase). The red arrow represents the atomic displacement of the Ge atom along the [111] direction.

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