Transport Through a Quantum Dot with Electron-Phonon Interaction

TL;DR

This paper theoretically investigates how electron-phonon interactions affect electrical transport in a quantum dot, revealing distinct spectral features for optical and acoustic phonons and effects of external modulation.

Contribution

It introduces a comprehensive theoretical analysis of electron-phonon interactions in quantum dot transport, including temperature effects and spectral features under different phonon couplings.

Findings

Optical phonon interaction creates a subpeak in the spectrum.

Acoustic phonon interaction results in a continuous spectrum.

External time-modulation introduces parasite peaks in the spectrum.

Abstract

We theoretically study the electrical transport properties of a single level quantum dot connected to two normal conducting leads, which is coupled to the lattice vibrations. We determine the current through the quantum dot in two different situations: time-independent and time-averaged. In all situations we consider three cases: when there is no electron-phonon interaction, when the dot electrons interact with optical phonons or when they interact with acoustic phonons. At finite temperatures we take into account the temperature dependence of the chemical potential. We treat the electron-phonon interaction by the canonical transformation method. In the case of electron-longitudinal optical phonon interaction the spectrum contains a subpeak. In the case of electron-acoustic phonon interaction the spectrum is continuous. In the time-averaged situation many parasite peaks appear in the spectrum, due to the external time-modulation.