Metal-insulator phenomena in perovskites of transition metal oxide

Versatile metal-insulator phenomena arising from strong electron correlations show up in pseudo-cubic and layered perovskites of 3d transition metal oxide. Most of them are derived from the correlated insulators by controlling of the one-electron bandwidth, band filling and dimensionality. Overviews are presented on some critical behaviors of the generalized Mott transitions in the perovskites which show, in general, a close interplay between the spin, charge and orbital degrees of freedom.