Influence of finite hund rules and charge transfer on properties of haldane systems
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 ΔC,ΔS, and several spin-spin correlation functions, including the hidden orde...
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| Autores principales: | , , |
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| Formato: | JOUR |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_10980121_v59_n15_p9916_Feiguin |
| Aporte de: |
| Sumario: | 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 ΔC,ΔS, and several spin-spin correlation functions, including the hidden order parameter Z(π), all properties converge slowly to the strong-coupling limit. When JH/t 2 and U/t 7 (the effective parameters that we obtain for Y2BaNiO5), ΔS is roughly half of the value expected from a strong-coupling expansion. © 1999 The American Physical Society. |
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