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arXiv · 2403.18019

Analytic method for quadratic polarons in nonparabolic bands

Serghei N. Klimin·Jacques Tempere·Matthew Houtput·Stefano Ragni·Thomas Hahn·Cesare Franchini·Andrey S. Mishchenko
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Abstract

Including the effect of lattice anharmonicity on electron-phonon interactions has recently garnered attention due to its role as a necessary and significant component in explaining various phenomena, including superconductivity, optical response, and temperature dependence of mobility. This study focuses on analytically treating the effects of anharmonic electron-phonon coupling on the polaron self-energy, combined with numerical Diagrammatic Monte Carlo data. Specifically, we incorporate a quadratic interaction into the method of squeezed phonon states, which has proven effective for analytically calculating the polaron parameters. Additionally, we extend this method to nonparabolic finite-width conduction bands while maintaining the periodic translation symmetry of the system. Our results are compared with those obtained from Diagrammatic Monte Carlo, partially reported in a recent study [S. Ragni et al., Phys. Rev. B 107, L121109(2023)], covering a wide range of coupling strengths for the nonlinear interaction. Remarkably, our analytic method predicts the same features as the Diagrammatic Monte Carlo simulation.

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Serghei N. Klimin, Jacques Tempere, Matthew Houtput, Stefano Ragni, Thomas Hahn, Cesare Franchini, Andrey S. Mishchenko. 2024-03-26. Analytic method for quadratic polarons in nonparabolic bands. https://doi.org/10.1103/physrevb.110.075107

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