Spin-thermoelectric transport induced by interactions and spin-flip processes in two dimensional topological insulators

TL;DR

This paper investigates how interactions and spin-flip processes in two-dimensional topological insulators influence thermoelectric transport, enabling control over spin currents and the potential for pure spin current generation.

Contribution

It reveals that combined effects of spin-flip processes and electron-electron interactions can produce and tune pure spin currents in topological insulator edge states.

Findings

Finite longitudinal spin current arises from spin-flip processes and interactions.

Gate voltages can tune the spin current's sign and magnitude.

Pure spin current with zero charge current can be generated.

Abstract

We consider thermoelectric transport properties of the edge states of a two dimensional topological insulator in a double quantum point contact geometry coupled to two thermally biased reservoirs. Both spin-preserving and spin-flipping tunneling processes between opposite edges are analyzed in the presence of electron-electron interactions. We demonstrate that the simultaneous presence of spin-flipping processes and interactions gives rise to a finite longitudinal spin current. Moreover, its sign and amplitude can be tuned by means of gate voltages with the possibility to generate a pure spin current, with a vanishing charge current.