Entanglement and manipulation of the magnetic and spin-orbit order in multiferroic Rashba semiconductors

TL;DR

This paper demonstrates how multiferroic (GeMn)Te exhibits giant Rashba splitting and tunable spin textures due to its coupled ferroelectric and magnetic orders, enabling potential applications in reprogrammable spintronic devices.

Contribution

It reveals the entanglement of magnetic and spin-orbit order in multiferroic (GeMn)Te and demonstrates manipulation of spin textures via magnetic fields, highlighting new functionalities for spintronic applications.

Findings

Giant Rashba splitting in (GeMn)Te inherited from {e1}-GeTe

Tunable Zeeman gap of up to 100 meV at the Dirac point

Manipulation of spin texture through magnetic field application

Abstract

The interplay between electronic eigenstates, spin, and orbital degrees of freedom, combined with fundamental breaking of symmetries is currently one of the most exciting fields of research. Multiferroics such as (GeMn)Te fulfill these requirements providing unusual physical properties due to the coexistence and coupling between ferromagnetic and ferroelectric order in one and the same system. Here we show that multiferroic (GeMn)Te inherits from its parent ferroelectric {\alpha}-GeTe compound a giant Rashba splitting of three-dimensional bulk states which competes with the Zeeman spin splitting induced by the magnetic exchange interactions. The collinear alignment of ferroelectric and ferromagnetic polarization leads to an opening of a tunable Zeeman gap of up to 100 meV around the Dirac point of the Rashba bands, coupled with a change in spin texture by entanglement of magnetic and spin-orbit order. Through applications of magnetic fields, we demonstrate manipulation of spin- texture by spin resolved photoemission experiments, which is also expected for electric fields based on the multiferroic coupling. The control of spin helicity of the bands and its locking to ferromagnetic and ferroelectric order opens fascinating new avenues for highly multifunctional multiferroic Rashba devices suited for reprogrammable logic and/or nonvolatile memory applications.