The development of spintronic devices has been limited by the poor compatibility between semiconductors and ferromagnetic sources of spin. The broken inversion symmetry of some semiconductors may allow for spin–charge interconversion, but its control by electric fields is volatile. This has led to interest in ferroelectric Rashba semiconductors, which combine semiconductivity, large spin–orbit coupling and non-volatility. Here we report room-temperature, non-volatile ferroelectric control of spin-to-charge conversion in epitaxial germanium telluride films. We show that ferroelectric switching by electrical gating is possible in germanium telluride, despite its high carrier density. We also show that spin-to-charge conversion has a similar magnitude to what is observed with platinum, but the charge current sign is controlled by the orientation of ferroelectric polarization. Comparison between theoretical and experimental data suggests that the inverse spin Hall effect plays a major role in switchable conversion.
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C.R. acknowledges financial support by Fondazione Cariplo and Regione Lombardia (grant no. 2017-1622 (ECOS)). C.R. and S. Picozzi acknowledge support from the Italian Ministry of Universities and Research (MUR) under the PRIN programme, project no. 2017YCTB59 (towards ferroelectricity in two dimensions (TWEET)). M.B. acknowledges support from the European Research Council through the Advanced Grant ‘FRESCO’ no. 833973. J.S. acknowledges Rosalind Franklin Fellowship from the University of Groningen. We acknowledge financial support by ANR French National Research Agency Toprise (no. ANR-16-CE24-0017), ANR French National Research Agency OISO (no. ANR-17-CE24-0026), ANR French National Research Agency CONTRABASS (no. ANR-20-CE24-0023) and the Laboratoire d’excellence LANEF (no. ANR-10-LABX-51-01). We are grateful to the EPR facilities available at the National TGE RPE facilities (no. IR 3443) and to the High Performance Computing Center at the University of North Texas and the Texas Advanced Computing Center at the University of Texas, Austin. We acknowledge A. Brenac, J.-F. Jacquot, C. Lombard and S. Gambarelli for their help and advice on the FMR measurement setup. We are grateful to O. Klein, M. Jamet, F. Yu, T. Guillet, M. Guimarães, D. Di Sante, F. Pezzoli, V. Garcia and S. Fusil for helpful discussions. We thank C. Stemmler and S. Behnke for technical support with the MBE system. This work was partially performed at PoliFAB, the micro- and nanofabrication facility of the Politecnico di Milano.
The authors declare no competing interests.
Peer review information Nature Electronics thanks Chih-Huang Lai and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
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Varotto, S., Nessi, L., Cecchi, S. et al. Room-temperature ferroelectric switching of spin-to-charge conversion in germanium telluride. Nat Electron 4, 740–747 (2021). https://doi.org/10.1038/s41928-021-00653-2
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