Conditions for requiring nonlinear thermoelectric transport theory in nanodevices

TL;DR

This paper investigates when nonlinear thermoelectric transport theory is necessary in nanodevices, showing that linear theory often suffices even under temperature gradients, across various quantum regimes.

Contribution

It provides a detailed numerical comparison demonstrating the robustness of linear transport theory in quantum dots under certain conditions.

Findings

Linear theory is robust at the average temperature in various regimes.

Nonlinear effects are less significant than previously claimed in temperature-driven currents.

The study covers resonant tunneling, Coulomb blockade, and Kondo regimes.

Abstract

In this paper, we examine the conditions under which the nonlinear transport theory is inescapable, when a correlated quantum dot is symmetrically coupled to two leads submitted to temperature and voltage biases. By detailed numerical comparisons between nonlinear and linear currents, we show that the claimed nonlinear behavior in a temperature gradient for the electric current is not so genuine, and the linear theory made at the operating temperature $\bar{T}= (T_H+T_C)/2$ is unexpectedly robust. This is demonstrated for the single impurity Anderson model, in different regimes: resonant tunneling, Coulomb blockade and Kondo regimes.