Abstract

The family of 3d transition metal oxide is known as strongly correlated electron systems, whose low energy properties are dominated by strong on-site Coulomb repulsion and Pauli’s exclusion principle. Typically, these systems are insulating with finite charge gap at a half filling of conduction band (Mott insulator). In contrast with the conventional band insulators, such as semiconductors, the electronic structure of the transition metal oxides is determined by the strong interaction of electrons themselves. Because of the strong correlation of spins and charges of such system, drastic change in the electronic and magnetic properties easily occurs by chemical doping, for instance the appearance of High-T_c), superconductivity, and colossal magnetoresistance, etc.

© 1999 Optical Society of America