Optically tunable spin transport on the surface of a topological insulator

TL;DR

This paper theoretically investigates how off-resonant high-frequency electromagnetic waves alter spin transport on the surface of a topological insulator, revealing anisotropic energy spectra and suppressed spin currents relevant for spinoptronics.

Contribution

It introduces a theoretical model describing the impact of strong light-matter coupling on spin dynamics in topological insulators, highlighting anisotropic effects and spin current suppression.

Findings

Electromagnetic irradiation induces anisotropy in the electron energy spectrum.

Irradiation suppresses spin currents on the TI surface.

Strong coupling modifies spin properties significantly.

Abstract

The emerging field of spinoptronics has a potential to supersede the functionality of modern electronics, while a proper description of strong light-matter coupling pose the most intriguing questions from both fundamental scientific and technological perspectives. In this paper we address a highly relevant issue for such a development. We theoretically explore spin dynamics on the surface of a 3D topological insulator (TI) irradiated with an off-resonant high-frequency electromagnetic wave. The strong coupling between electrons and the electromagnetic wave drastically modifies the spin properties of TI. The effects of irradiation are shown to result in anisotropy of electron energy spectrum near the Dirac point and suppression of spin current and are investigated in detail in this work.