Strongly-Correlated Thermoelectric Transport beyond Linear Response

TL;DR

This paper develops a theoretical framework to analyze nonlinear thermoelectric transport in strongly correlated quantum impurity systems, revealing many-body effects beyond mean-field approximations.

Contribution

It introduces an effective-equilibrium density matrix approach for nonlinear transport in strongly interacting quantum impurities with arbitrary chemical potentials.

Findings

Transport can be described by an effective equilibrium density matrix.

Strong correlations cause particle-hole symmetry breaking.

Results align with experimental observations of many-body effects.

Abstract

We investigate nonlinear thermoelectric transport through quantum impurity systems with strong on-site interactions. We show that the steady-state transport through interacting quantum impurities in contact with electron reservoirs at significantly different temperatures can be captured by an effective-equilibrium density matrix, expressed compactly in terms of the Lippmann-Schwinger operators of the system. In addition, the reservoirs can be maintained at arbitrary chemical potentials. The interplay between the temperature gradient and bias voltage gives rise to a non-trivial breaking of particle-hole symmetry in the strongly correlated regime, manifest in the Abrikosov-Suhl localized electron resonance. This purely many-body effect, which is in agreement with experimental results, is beyond the purview of mean-field arguments.