Switchable enhanced spin photocurrent in Rashba and cubic Dresselhaus ferroelectric semiconductors

TL;DR

This paper predicts a highly efficient, switchable spin photocurrent in ferroelectric semiconductors driven by spin-orbit interactions, enabling control of spin currents with light and electric fields, demonstrated through first-principles simulations.

Contribution

It introduces a novel mechanism for generating and switching spin photocurrents in ferroelectrics via Rashba and cubic Dresselhaus SOIs, distinct from the Edelstein effect.

Findings

Spin photocurrent is about 100 times larger than charge photocurrent.

Electric field can switch the direction of the spin photocurrent.

First-principles calculations confirm the predicted effects in {}-GeTe.

Abstract

Generating and controlling spin current (SC) are of central interest in spin physics and applications. To date, the spin-orbit interaction (SOI) is an established pathway to generate SC through the spin-charge current conversion. We predict an efficient spin-light conversion via the Rashba and higher-order cubic Dresselhaus SOIs in ferroelectrics. Different from the known Edelstein effect, where SC is created by the nonequilibrium spin density, our predicted spin-polarized current is from direct interactions between light and unique spin textures generated by SOI in ferroelectrics. Using first-principles simulations, we demonstrate these concepts by calculating the DC spin photocurrent in a prototypical Rashba ferroelectric, {\alpha}-GeTe. The photo-induced SC is about two orders of magnitude larger than the charge photocurrent. More importantly, we can conveniently switch the direction of SC by an applied electric field via inverting the spin textures. These predictions give hope to generating and controlling light-driven SC via nonvolatile electric-field.