The role of electron-electron collisions for magnetotransport at intermediate temperatures

TL;DR

This paper investigates how electron-electron and electron-impurity scattering influence magnetotransport properties in disordered electronic systems at intermediate temperatures, revealing effects like sign changes in the Seebeck coefficient and maxima in the Nernst coefficient.

Contribution

It demonstrates the significant impact of momentum-dependent electron-impurity scattering on thermomagnetic effects and provides methods to measure scattering rates through temperature and magnetic field dependence.

Findings

Seebeck coefficient can change sign due to momentum-dependent scattering.

Nernst coefficient exhibits a maximum at finite temperatures with momentum dependence.

Hall and Righi-Leduc coefficients are weakly affected by scattering momentum dependence.

Abstract

We discuss galvanomagnetic and thermomagnetic effects in disordered electronic systems focusing on intermediate temperatures, for which electron-electron scattering and electron-impurity scattering occur at similar rates, while phonon-related effects can be neglected. In particular, we explore how electric and thermal currents driven either by an electric field or by a temperature gradient are affected by the interplay of momentum-dependent electron-impurity scattering, electron-electron scattering, and the presence of a magnetic field. We find that the electric resistance, the Seebeck coefficient and the Nernst coefficient are particularly sensitive to the momentum dependence of the electron-impurity scattering rate at intermediate temperatures. A sufficiently strong momentum dependence of the electron-impurity scattering rate can induce a sign change of the Seebeck coefficient. This sign change can be suppressed by a perpendicular magnetic field. The temperature and magnetic field dependence of the Seebeck coefficient can be used for measuring the magnitude of the electron-impurity and electron-electron scattering rates. The Nernst coefficient vanishes for momentum-independent electron-impurity scattering, but displays a maximum at finite temperatures once the momentum dependence is accounted for. By contrast, the Hall coefficient and the Righi-Leduc coefficient display only a weak dependence on the momentum dependence of the electron-impurity scattering at intermediate temperatures.