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arXiv · 1110.0648

Heavy-Electron Formation and Bipolaronic Transition in the Anharmonic Holstein Model

Takahiro Fuse·Yoshiaki Ono·Takashi Hotta
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Abstract

The emergence of the bipolaronic phase and the formation of the heavy-electron state in the anharmonic Holstein model are investigated using the dynamical mean-field theory in combination with the exact diagonalization method. For a weak anharmonicity, it is confirmed that the first-order polaron-bipolaron transition occurs from the observation of a discontinuity in the behavior of several physical quantities. When the anharmonicity is gradually increased, the polaron-bipolaron transition temperature is reduced as well as the critical values of the electron-phonon coupling constant for polaron-bipolaron transition. For a strong anharmonicity, the polaron-bipolaron transition eventually changes to a crossover behavior. The effect of anharmonicity on the formation of the heavy-electron state near the polaron-bipolaron transition and the crossover region is discussed in detail.

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Takahiro Fuse, Yoshiaki Ono, Takashi Hotta. 2012-03-11. Heavy-Electron Formation and Bipolaronic Transition in the Anharmonic Holstein Model. https://doi.org/10.1143/jpsj.81.044701

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