Nonlinear Seebeck and Peltier Effects in Quantum Point Contacts

TL;DR

This paper investigates the nonlinear Seebeck and Peltier effects in quantum point contacts by expanding charge and entropy currents in powers of bias and temperature difference, analyzing third-order nonlinearities.

Contribution

It introduces a detailed expansion approach for nonlinear thermoelectric effects in quantum point contacts, highlighting third-order nonlinear terms and their dependence on contact parameters.

Findings

Third-order nonlinear terms dominate the Seebeck and Peltier effects.

Behavior of nonlinear coefficients varies with contact parameters.

Nonlinear effects become significant at higher bias and temperature differences.

Abstract

The charge and entropy currents across a quantum point contact is expanded as a series in powers of the applied bias voltage and the temperature difference. After that, the expansions of the Seebeck voltage in temperature difference and the Peltier heat in current are obtained. With a suitable choice of the average temperature and chemical potential, the lowest order nonlinear term in both cases appear to be of third order. The behavior of the third-order coefficients in both cases are then investigated for different contact parameters.