Tunneling resonances in quantum dots: Coulomb interaction modifies the width

TL;DR

This paper investigates how Coulomb interactions influence the width of tunneling resonances in quantum dots, revealing a polarity-dependent broadening effect through experimental and theoretical analysis.

Contribution

It introduces a detailed analysis linking Coulomb interaction to the polarity-dependent broadening of quantum dot states in resonant tunneling structures.

Findings

Broadening of I–V steps depends strongly on bias polarity.

Coulomb interaction causes a clear polarity-dependent effect.

Experimental data aligns with non-equilibrium transport theory.

Abstract

Single-electron tunneling through a zero-dimensional state in an asymmetric double-barrier resonant-tunneling structure is studied. The broadening of steps in the $I$--$V$ characteristics is found to strongly depend on the polarity of the applied bias voltage. Based on a qualitative picture for the finite-life-time broadening of the quantum dot states and a quantitative comparison of the experimental data with a non-equilibrium transport theory, we identify this polarity dependence as a clear signature of Coulomb interaction.