Quasiparticle properties of the nonlinear Holstein model at finite doping and temperature

Article

关键词: CHARGE-DENSITY-WAVE;    QUANTUM MONTE-CARLO;    ELECTRONIC-STRUCTURE;    SUPERCONDUCTIVITY;    TRANSITION;    DYNAMICS;   

DOI  :  10.1103/PhysRevB.92.064301

来源: SCIE

【 摘 要 】

We use determinant quantum Monte Carlo to study the single-particle properties of quasiparticles and phonons in a variant of the two-dimensional Holstein model that includes an additional nonlinear electron-phonon (e-ph) interaction. We find that a small positive nonlinear interaction reduces the effective coupling between the electrons and the lattice, suppresses charge-density-wave (CDW) correlations, and hardens the effective phonon frequency. Conversely, a small negative nonlinear interaction can enhance the e-ph coupling resulting in heavier quasiparticles, an increased tendency towards a CDW phase at all fillings, and a softened phonon frequency. An effective linear model with a renormalized interaction strength and phonon frequency can qualitatively capture this physics; however, the quantitative effects of the nonlinearity on both the electronic and phononic degrees of freedom cannot be captured by such a model. These results are significant for typical nonlinear coupling strengths found in real materials, indicating that nonlinearity can have an important influence on the physics of many e-ph coupled systems.

【 授权许可】

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