Dependence of the polarizability of the $Cu_4O_8$ cluster on the doping, the weight of the oxygen-hole state, and the excitation gaps in the three-band Hubbard model

Ramasesha, S and Rao, CNR (1991) Dependence of the polarizability of the $Cu_4O_8$ cluster on the doping, the weight of the oxygen-hole state, and the excitation gaps in the three-band Hubbard model. In: Physical Review B, 44 (13). pp. 7046-7050.

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Abstract

We have obtained the model exact static polarizability of the $Cu_4O_8$ cluster within the three-band Hubbard model for different doping levels. The excitation gaps as well as the weight of the $O^-$ (oxygen-hole) state in the ground-state wave function have been exactly computed. The parameters of the model are varied to alter the excitation gaps as well as the weight of the $O^-$ state in order to examine the dependence of the polarizability on these quantities. The $Cu_4O_8$ cluster is highly polarizable, the polarizability increasing with the doping level. The polarizability is large when the excitation gap is charge-transfer-like and increases with the decreasing gaps; it also increases markedly with the increase in the weight of the $O^-$ state. Experimentally, the $T_c$ in the cuprates is highest for the range of the weight of $O^-$ for which the lattice is highly polarizable.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	The American Physical Society
Additional Information:	Copyright of this article belongs to the American Physical Society.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	06 Sep 2006
Last Modified:	19 Sep 2010 04:31
URI:	http://eprints.iisc.ac.in/id/eprint/8500

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