Ferroelectric control of the spin texture in germanium telluride

TL;DR

This paper demonstrates the first experimental control of spin texture in a semiconductor using ferroelectric polarization in GeTe, paving the way for non-volatile spintronic devices.

Contribution

It provides the first experimental evidence of ferroelectric control over spin textures in a bulk semiconductor, specifically GeTe, via spin-resolved photoemission.

Findings

Opposite spin circulation in GeTe surfaces with different ferroelectric polarizations.

Demonstration of electric field control of spin textures in a bulk semiconductor.

Potential for non-volatile spintronic device applications.

Abstract

The electrical manipulation of spins in semiconductors, without magnetic fields or auxiliary ferromagnetic materials, represents the holy grail for spintronics. The use of Rashba effect is very attractive because the k-dependent spin-splitting is originated by an electric field. So far only tiny effects in two-dimensional electron gases (2DEG) have been exploited. Recently, GeTe has been predicted to have bulk bands with giant Rashba-like splitting, originated by the inversion symmetry breaking due to ferroelectric polarization. In this work, we show that GeTe(111) surfaces with inwards or outwards ferroelectric polarizations display opposite sense of circulation of spin in bulk Rashba bands, as seen by spin and angular resolved photoemission experiments. Our results represent the first experimental demonstration of ferroelectric control of the spin texture in a semiconductor, a fundamental milestone towards the exploitation of the non-volatile electrically switchable spin texture of GeTe in spintronic devices.