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Degeneracy of Ground State in Two-dimensional Electron-Lattice System

Tetsuya Hamano·Yoshiyuki Ono
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Abstract

We discuss the ground state of a two dimensional electron-lattice system described by a Su-Schrieffer-Heeger type Hamiltonian with a half-filled electronic band, for which it has been pointed out in the previous paper [J. Phys. Soc. Jpn. 69 (2000) 1769-1776] that the ground state distortion pattern is not unique in spite of a unique electronic energy spectrum and the same total energy. The necessary and sufficient conditions to be satisfied by the distortion patterns in the ground state are derived numerically. As a result the degrees of degeneracy in the ground state is estimated to be about $N^{N/4}$ for $N \gg 1$ with $N$ the linear dimension of the system.

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Tetsuya Hamano, Yoshiyuki Ono. 2001-04-25. Degeneracy of Ground State in Two-dimensional Electron-Lattice System. https://doi.org/10.1143/jpsj.70.1849

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