Spin-resolved electronic structure of ferroelectric {\alpha}-GeTe and multiferroic Ge1-xMnxTe

TL;DR

This study investigates the spin-resolved electronic structure of ferroelectric {1}-GeTe and multiferroic Ge1-xMnxTe, revealing how doping and external fields influence spin textures and Rashba splitting, with implications for spintronic devices.

Contribution

It provides a comprehensive experimental and theoretical analysis of the spin textures and electronic structure in ferroelectric and multiferroic GeTe-based materials, including effects of Mn doping and external fields.

Findings

Disentangled bulk, surface, and resonance states in electronic structure.

Mapped spin textures and Rashba splitting evolution under external fields.

Developed a model fitting experimental and theoretical data.

Abstract

Germanium telluride features special spin-electric effects originating from spin-orbit coupling and symmetry breaking by the ferroelectric lattice polarization, which opens up many prospectives for electrically tunable and switchable spin electronic devices. By Mn doping of the {\alpha}-GeTe host lattice, the system becomes a multiferroic semiconductor possessing magnetoelectric properties in which the electric polarization, magnetization and spin texture are coupled to each other. Employing spin- and angle-resolved photoemission spectroscopy in bulk- and surface-sensitive energy ranges and by varying dipole transition matrix elements, we disentangle the bulk, surface and surface-resonance states of the electronic structure and determine the spin textures for selected parameters. From our results, we derive a comprehensive model of the {\alpha}-GeTe surface electronic structure which fits experimental data and first principle theoretical predictions and we discuss the unconventional evolution of the Rashba-type spin splitting upon manipulation by external B- and E-fields.