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Effect of electron-phonon interaction range on lattice polaron dynamics: a continuous-time quantum Monte Carlo study

P. E. Spencer·J. H. Samson·P. E. Kornilovitch·A. S. Alexandrov
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Abstract

We present the numerically exact ground state energy, effective mass, and isotope exponents of a one-dimensional lattice polaron, valid for any range of electron-phonon interaction, applying a new continuous-time Quantum Monte Carlo (QMC) technique in a wide range of coupling strength and adiabatic ratio. The QMC method is free from any systematic finite-size and finite-time-step errors. We compare our numerically exact results with analytical weak-coupling theory and with the strong-coupling $1/λ$ expansion. We show that the exact results agree well with the canonical Fröhlich and Holstein-Lang-Firsov theories in the weak and strong coupling limits, respectively, for any range of interaction. We find a strong dependence of the polaron dynamics on the range of interaction. An increased range of interaction has a similar effect to an increased (less adiabatic) phonon frequency: specifically, a reduction in the effective mass.

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P. E. Spencer, J. H. Samson, P. E. Kornilovitch, A. S. Alexandrov. 2005-04-10. Effect of electron-phonon interaction range on lattice polaron dynamics: a continuous-time quantum Monte Carlo study. https://doi.org/10.1103/physrevb.71.184310

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