Spin-orbit coupling effects in materials with broken inversion symmetry are responsible for peculiar spin textures. Among them, ferroelectric materials allow for non-volatile control of the spin degree of freedom through the non-volatile electrical inversion of the spin texture, through to their reversible spontaneous polarization. Such functionality holds potential for technological applications exploiting spin effects controlled by electric fields. The ferroelectric Rashba semiconductor Germanium Telluride stands out as material for Spin-Orbitronics: its ferroelectricity provides a nonvolatile state variable able to generate and drive a giant bulk Rashba-type spin splitting of the electronic bands, while its semiconductivity would allow for the realization of spin-based transistors. The ferroelectric control of the bands topology and of the spin texture is expected to reflect in the tunability of the spin transport properties. Here we exploit the unidirectional spin Hall magnetoresistance of Fe/GeTe heterostructures to characterize charge-to-spin conversion in GeTe. Our preliminary results indicate a sizable conversion efficiency at low temperature (120 K), which promotes ferroelectric Rashba semiconductors as promising candidates for the implementation of non-volatile electrically reconfigurable computing devices based on spin transport in semiconductors.

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S. Varotto, L. Nessi, S. Cecchi, R. Calarco, R. Bertacco, and C. Rinaldi, "Investigation of charge-to-spin conversion in GeTe," Proc. SPIE 10732, Spintronics XI, 107320C (Presented at SPIE Nanoscience + Engineering: August 19, 2018; Published: 20 September 2018); https://doi.org/10.1117/12.2320502.