Effects of electron-phonon interaction on non-equilibrium transport through single-molecule transistor

TL;DR

This paper investigates how electron-phonon interactions influence non-equilibrium transport in single-molecule transistors, revealing tunable spectral features and transport properties affected by bias and gate voltages.

Contribution

It introduces a nonperturbative approach to analyze electron-phonon effects on quantum transport, highlighting the sensitivity of spectral functions to bias and the breaking of particle-hole symmetry.

Findings

Spectral functions are sensitive to lead chemical potentials.

EPI causes red-shift, sharpening, and phonon sidebands.

Transport properties are significantly affected at low temperatures.

Abstract

On the basis of the nonequilibrium Green's function and nonperturbative canonical transformation for the local electron-phonon interaction (EPI), the quantum transport through a single-molecule transistor(SMT) has been investigated with a particular attention paid to the joint effect of the EPI and SMT-lead coupling on the spectral function and conductance. In addition to the usual EPI-induced renormalized effects (such as the red-shift, sharpening, and phonon-sidebands of the SMT level), owing to improved disentagling the electron-phonon system, it has been found that, the profile of the spectral function of the SMT electron is sensitive to lead chemical potentials, thus can readily be manipulated by tuning the bias as well as the SMT-gate voltage. As a consequence, the broken particle-hole symmetry in this system can be clearly recognized through the phonon sidebands in the spectral function. These EPI effects also manifest themselves in the nonequilibrium transport properties of the SMT, particularly at low temperature.