Entanglement of the spin-orbit and magnetic order in multiferroic materials bears a strong potential for engineering novel electronic and spintronic devices. Here, we explore the electron and spin structure of ferroelectric α-GeTe thin films doped with ferromagnetic Mn impurities to achieve its multiferroic functionality. We use bulk-sensitive soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES) to follow hybridization of the GeTe valence band with the Mn dopants. We observe a gradual opening of the Zeeman gap in the bulk Rashba bands around the Dirac point with increase of the Mn concentration, indicative of the ferromagnetic order, at persistent Rashba splitting. Furthermore, subtle details regarding the spin-orbit and magnetic order entanglement are deduced from spin-resolved ARPES measurements. We identify antiparallel orientation of the ferroelectric and ferromagnetic polarization, and altering of the Rashba-type spin helicity by magnetic switching. Our experimental results are supported by first-principles calculations of the electron and spin structure.

Department of Chemistry Ludwig Maximillian University 81377 Munich Germany

Institut für Halbleiter und Festkörperphysik Johannes Kepler Universität A 4040 Linz Austria

Institute of Physics École Polytechnique Fédérale de Lausanne CH 1015 Lausanne Switzerland

National Technical University Kharkiv Polytechnic Institute Frunze Str 21 61002 Kharkiv Ukraine

New Technologies Research Center University of West Bohemia Plzeň Czech Republic

SOLEIL Synchrotron L'Orme des Merisiers F 91192 Gif sur Yvette France

Swiss Light Source Paul Scherrer Institut CH 5232 Villigen PSI Switzerland

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Efficient magnetic switching in a correlated spin glass