Non-linear magneto-transport through small quantum dots at strong intra-dot correlations

TL;DR

This paper investigates nonlinear electron transport through small quantum dots under strong intra-dot Coulomb interactions, revealing deviations from equilibrium statistics and deriving relations between current steps and spectral degeneracy.

Contribution

It formulates nonequilibrium self-consistent mean field equations for strongly correlated quantum dots and provides analytical relations linking current features to spectral degeneracy.

Findings

Bias voltage causes populations to equalize even at low temperature.

Analytical relations between current step heights and spectral degeneracy are derived.

Strong intra-dot interactions lead to significant deviations from Gibbs statistics.

Abstract

Nonlinear transport through a quantum dot is studied in the limit of weak and strong intra-dot Coulomb interaction. For the latter regime the nonequilibrium self-consistent mean field equations for energies and spectral weights of one-electron transitions are formulated. The increase of the bias-voltage window leads to a strong deviation from Gibbs statistics: the populations of states involved into a tunnelling are equalizing in this limit even at low temperature. For a symmetric coupling of a quantum dot to two leads we provide simple analytical relations between heights of the current steps and degeneracy of a spectrum in a two-dimensional parabolic dot in a perpendicular magnetic field in the both regimes.