Negative differential resistance due to the resonance coupling of a quantum-dot dimer

TL;DR

This paper investigates how resonance coupling in a quantum-dot dimer causes negative differential resistance in electron tunneling, with the effect depending on temperature and dot-dot coupling.

Contribution

It demonstrates that resonance coupling between quantum dots induces NDR, highlighting the temperature dependence and the influence of dot-dot coupling on the phenomenon.

Findings

Resonance coupling causes a peak in the I-V curve at low temperature.

The peak height and width depend on the dot-dot coupling.

The NDR peak disappears at high temperature due to thermal effects.

Abstract

Electron tunneling through a coupled quantum-dot dimer under a dc-bias is investigated. We find that a peak in the $I$-$V$ curve appears at low temperature when two discrete electronic states in the two quantum dots are aligned with each other -- resonance coupling. This leads to a negative differential resistance. The peak height and width depend on the dot-dot coupling. At high temperature, the peak disappears due to thermal smearing effects.