Zero-bias anomalies and boson-assisted tunneling through quantum dots

TL;DR

This paper investigates how strong Coulomb interactions and bosonic environments influence resonant tunneling through quantum dots, revealing complex spectral features and zero-bias anomalies consistent with experimental observations.

Contribution

It introduces a real-time approach to analyze spectral density and nonlinear current, highlighting the impact of boson-assisted processes on Kondo peaks and conductance anomalies.

Findings

Spectral density exhibits split Kondo peaks due to voltage and boson frequencies.

Zero-bias conductance shows a local maximum or minimum depending on level position.

Results align with recent experimental data on quantum dot tunneling.

Abstract

We study resonant tunneling through a quantum dot with one degenerate level in the presence of a strong Coulomb repulsion and a bosonic environment. Using a real-time approach we calculate the spectral density and the nonlinear current within a conserving approximation. The spectral density shows a multiplet of Kondo peaks split by the transport voltage and boson frequencies. As a consequence we find a zero-bias anomaly in the differential conductance which can show a local maximum or minimum depending on the level position. The results are compared with recent experiments.