Vibrational Sidebands and Kondo-effect in Molecular Transistors

TL;DR

This paper investigates electron transport in molecular quantum dots within the Kondo regime, revealing vibrational sidebands in conductance influenced by electron-vibron interactions and gate voltage, with analytical and numerical methods.

Contribution

It introduces a generalized Schrieffer-Wolff transformation to model spin-vibron interactions and analyzes Kondo sidebands and conductance behavior in molecular transistors.

Findings

Kondo sidebands appear at multiples of vibron frequency

Side-peak intensities depend strongly on gate voltage

Weak coupling regime allows analytical conductance calculations

Abstract

Electron transport through molecular quantum dots coupled to a single vibrational mode is studied in the Kondo regime. We apply a generalized Schrieffer-Wolff transformation to determine the effective low-energy spin-spin-vibron-interaction. From this model we calculate the nonlinear conductance and find Kondo sidebands located at bias-voltages equal to multiples of the vibron frequency. Due to selection rules, the side-peaks are found to have strong gate-voltage dependences, which can be tested experimentally. In the limit of weak electron-vibron coupling, we employ a perturbative renormalization group scheme to calculate analytically the nonlinear conductance.