Transport via a Quantum Shuttle

TL;DR

This paper explores how quantum vibrational modes influence electron transport in a quantum dot system, revealing current peaks linked to avoided level crossings and phonon-assisted tunneling mechanisms.

Contribution

It introduces a quantum treatment of vibrational modes in a quantum shuttle, highlighting the role of phonons in transport and energy dissipation mechanisms.

Findings

Current-voltage peaks correspond to avoided level crossings.

Transport involves phonon creation, aiding tunneling.

Quantum vibrational effects significantly impact electron transport.

Abstract

We investigate the effect of quantisation of vibrational modes on a system in which the transport path is through a quantum dot mounted on a cantilever or spring such that tunnelling to and from the dot is modulated by the oscillation. We consider here the implications of quantum aspects of the motion. Peaks in the current voltage characteristic are observed which correspond to avoided level crossings in the eigenvalue spectrum. Transport occurs through processes in which phonons are created. This provides a path for dissipation of energy as well as a mechanism for driving the oscillator, thus making it easier for electrons to tunnel onto and off the dot and be ferried across the device.