Conductance of a molecule with a center of mass motion

TL;DR

This paper investigates how a molecule's center of mass vibrations influence its electrical conductance, revealing suppression effects linked to vibrational modes and symmetry breaking.

Contribution

It introduces models connecting molecular vibrations to conductance suppression, highlighting the role of symmetry and occupancy in electron transport.

Findings

Conductance is suppressed at non-integer molecular occupancy.

Dynamic inversion symmetry breaking affects conductance when CM mode is decoupled from electron density.

Vibrational modes modulate electron transport properties.

Abstract

We calculate the zero temperature conductance and characteristic correlation functions of a molecule with a center of mass (CM) motion which modulates couplings to the leads. In the first model studied, the CM vibrational mode is simultaneously coupled to the electron density on the molecule. The conductance is suppressed in regimes corresponding to non-integer occupancy of the molecule. In the second model, where the CM mode is not directly coupled to the electron density, the suppression of conductance is related to the dynamic breaking of the inversion symmetry.