[Article] - Spin texture of α-GeTe in the ultrathin regime

Sous titre
Ferroelectric Rashba semiconductors such as α-GeTe have recently emerged as promising candidates for all-electrically controlled spin-orbitronics. The persistence of Rashba spin-split electronic states in ultrathin α-GeTe films is of utmost importance in the context of device downscaling. Using spin- and angle-resolved photoemission spectroscopy supported by first-principle calculations, the authors here demonstrate that α-GeTe films as thin as 5 nm still exhibit an in-plane spin texture at the Fermi surface.

Abstract

Using spin- and angle-resolved photoemission spectroscopy combined with density functional theory calculations, we investigate the electronic structure of α-GeTe grown on a Si(111)-Sb substrate in the ultrathin limit. The full band structure, including the Fermi surface, and spin texture characterizations are presented, with a focus on a film thickness of 5 nm. Well-defined spin-polarized quantum well bulk states are evidenced. This confirms the high quality of elaborated ultrathin films and allows precise determination of the thickness. The Rashba splitting and the in-plane spin texture of GeTe bulk bands are shown to be fully preserved on the Si(111)-Sb substrate. This suggests the persistence of inversion symmetry breaking and ferroelectric properties in the ultrathin limit of GeTe films. Our results demonstrate that device downscaling can be pursued in the context of all-electrically controlled spin-orbitronics applications.
 

Authors

Calvin Tagne-Kaegom,1 Alexandre Llopez,2 Boris Croes,2, Geoffroy Kremer, 1 Bertrand Kierren , 1 Daniel Malterre,1 Luc Moreau , 1 Jaurès Fotié Ngoufo , 2 Stefano Curiotto , 2 Pierre Müller , 2 Patrick Le Fèvre , 3,‡Julien Rault,3 François Bertran , 3 Andrés Saúl , 2 Frédéric Leroy , 2 Fabien Cheynis , 2,† and Yannick Fagot-Revurat,1 

1-Université de Lorraine, CNRS, Institut Jean Lamour, 54000 Nancy, France 

2-Aix Marseille Univ., CNRS, CINAM, AMUtech, Marseille, France

3-Synchrotron SOLEIL, L’Orme des Merisiers, Départementale 128, F-91190 Saint-Aubin, France
 

References

C. Tagne-Kaegom et al., Physical Review B , Editor suggestion113, 125113 (2026), Editors’suggestion


DOI

https://doi.org/10.1002/adem.202503172

Image
spin-ARPES (left) and spin-polarized DFT (right) Fermi surface mapping