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Gap formation and soft phonon mode in the Holstein model

D. Meyer·A. C. Hewson·R. Bulla
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Abstract

We investigate electron-phonon coupling in many-electron systems using dynamical mean-field theory in combination with the numerical renormalization group. This non-perturbative method reveals significant precursor effects to the gap formation at intermediate coupling strengths. The emergence of a soft phonon mode and very strong lattice fluctuations can be understood in terms of Kondo-like physics due to the development of a double-well structure in the effective potential for the ions.

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D. Meyer, A. C. Hewson, R. Bulla. 2002-06-19. Gap formation and soft phonon mode in the Holstein model. https://doi.org/10.1103/physrevlett.89.196401

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