Phonon-drag magnetothermopower in Rashba spin-split two-dimensional electron systems

TL;DR

This paper investigates how Rashba spin-orbit interaction influences phonon-drag thermopower in a 2D electron system under magnetic field, revealing peak splitting and temperature dependence in GaAs/AlGaAs heterostructures.

Contribution

It demonstrates the direct effect of Rashba spin-orbit coupling on phonon-drag thermopower and analyzes its dependence on magnetic field and temperature.

Findings

Peak splitting in thermopower due to Rashba interaction

Power-law temperature dependence in the Bloch-Gruneisen regime

Extraction of temperature dependence exponent for various parameters

Abstract

We study phonon-drag contribution to the thermoelectric power in a quasi-two-dimensional electron system confined in GaAs/AlGaAs heterostructure in presence of both Rashba spin-orbit interaction and perpendicular magnetic field at very low temperature. It is observed that the peaks in the phonon-drag thermopower split into two when the Rashba spin-orbit coupling constant is strong. This splitting is a direct consequence of the Rashba spin-orbit interaction. We show the dependence of phonon-drag thermopower on both magnetic field and temperature numerically. A power-law dependence of phonon-drag magnetothermopower on the temperature in the Bloch-Gruneisen regime is found. We also extract the exponent of the temperature dependence of phonon-drag thermopower for different parameters like electron density, magnetic field, and the spin-orbit coupling constant.