Influence of finite Hund rules and charge transfer on properties of Haldane systems

Article

关键词: TRANSITION-METAL OXIDE;    KONDO-LATTICE MODEL;    BOND GROUND-STATES;    HUBBARD-MODEL;    HEISENBERG-ANTIFERROMAGNET;    ELECTRONIC-STRUCTURE;    SPIN DYNAMICS;    PHASE-DIAGRAM;    ONE-DIMENSION;    LINEAR-CHAIN;   

DOI  :  10.1103/PhysRevB.59.9916

来源: SCIE

【 摘 要 】

We consider the Kondo-Hubbard model with ferromagnetic exchange coupling JH, showing that it is an approximate effective model for late transition-metal-O linear systems. We study the dependence of the charge and spin gaps: Delta(C), Delta(S), and several spin-spin correlation functions, including the hidden order parameter Z(pi), as functions of J(H)/t and U/t, by numerical diagonalization of finite systems. Except for Z(pi), all properties converge slowly to the strong-coupling limit. When J(H)/t similar to 2 and U/t similar to 7 (the effective parameters that we obtain, for Y2BaNiO5), Delta(S) is roughly half Of the value expected from a strong-coupling expansion. [S0163-1829(99)05215-7].

【 授权许可】

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