Thermospin Hall effect generated by thermal influence and thermoelectric effect

TL;DR

This paper theoretically predicts a thermospin Hall effect in semiconductors, where a transverse spin current is generated by a temperature gradient influenced by spin-orbit coupling and thermoelectric effects.

Contribution

It introduces a theoretical framework for the thermospin Hall effect, highlighting the role of dynamical thermospin Hall conductivity and spin accumulation at edges in semiconductors.

Findings

Transverse spin current can be generated without net charge flow.

Interband optical transitions dominate spin manipulation.

Edge spin accumulation influences magnetization and field formation.

Abstract

In this paper, we present the theoretical predication of a thermospin Hall effect, in which a transverse spin current can be generated in semiconductors in the presence of spin-orbit coupling by a frequency-dependent longitudinal temperature gradient. Because of the thermoelectric effect, there is no net charge current but there is a heat flow from the hot side to the cold side. We perform the theoretical calculation of dynamical thermospin Hall conductivity in a two-dimensional Rashba spintronic system. It has been shown that the direct interband optical transition dominates the ordering and manipulation of spin in the generation of a transverse intrinsic spin current. In view of the role of the thermoelectric effect, the contributions to the thermospin Hall effect are classified as that originating from a direct contribution of thermal electronic diffusion and that from the compensatory electron flow in balance with the thermal diffusion. For a finite system, the analysis yields evidence that the spin accumulation around the edges of a plate determines the magnetization. In equilibrium, a field created by a magnetization gradient emerges in the direction perpendicular to the temperature gradient. The experimental observation of the thermospin Hall effect is proposed by measuring the longitudinal temperature difference with the injection of a transverse spin current and by analyzing the Hall angle. In addition, in order to achieve pure spin accumulation in the spin Hall effect, an extension of the thermospin Hall effect for exciting electron-hole pairs in semiconductors is proposed.