Charge and spin fluctuations Cu2+(S= 1 2)←→Cu3+(S=1)in HTSCs. new model of narrow impurity bands

Abstract

The energy band of oxide superconductors is theoretically investigated when charge and spin fluctuations of Cu2+ (S= 1 2)-O- (S=0) ←→ Cu3+ (S=1)-O2- (S= 1 2) take place. It is shown that two narrow bands arise near Fermi level under hole doping. The dynamic admixture of 3z2-r2 state to the x2-y2 state is equal to approximately 10%. © 1991.