Correlation-induced conductance suppression at level degeneracy in a quantum dot

TL;DR

This paper investigates conductance behavior in an InSb nanowire quantum dot, revealing correlation-induced suppression at level degeneracy and supporting findings with theoretical calculations.

Contribution

It demonstrates the occurrence of conductance suppression at level degeneracy in a quantum dot, a phenomenon linked to electron correlations and supported by numerical and analytical models.

Findings

Conductance enhancement due to Kondo effect for aligned levels with different spins.

Conductance suppression at levels with equal spins during alignment.

Observation of correlation-induced resonance within Coulomb blockade region.

Abstract

The large, level-dependent g-factors in an InSb nanowire quantum dot allow for the occurrence of a variety of level crossings in the dot. While we observe the standard conductance enhancement in the Coulomb blockade region for aligned levels with different spins due to the Kondo effect, a vanishing of the conductance is found at the alignment of levels with equal spins. This conductance suppression appears as a canyon cutting through the web of direct tunneling lines and an enclosed Coulomb blockade region. In the center of the Coulomb blockade region, we observe the predicted correlation-induced resonance, which now turns out to be part of a larger scenario. Our findings are supported by numerical and analytical calculations.