AbstractNonmagnetic Rashba systems with broken inversion symmetry are expected to exhibit nonreciprocal charge transport, a new paradigm of unidirectional magnetoresistance in the absence of ferromagnetic layer. So far, most work on nonreciprocal transport has been solely limited to cryogenic temperatures, which is a major obstacle for exploiting the room-temperature two-terminal devices based on such a nonreciprocal response. Here, we report a nonreciprocal charge transport behavior up to room temperature in semiconductor α-GeTe with coexisting the surface and bulk Rashba states. The combination of the band structure measurements and theoretical calculations strongly suggest that the nonreciprocal response is ascribed to the giant bulk Rashba spin splitting rather than the surface Rashba states. Remarkably, we find that the magnitude of the nonreciprocal response shows an unexpected non-monotonical dependence on temperature. The extended theoretical model based on the second-order spin–orbit coupled magnetotransport enables us to establish the correlation between the nonlinear magnetoresistance and the spin textures in the Rashba system. Our findings offer significant fundamental insight into the physics underlying the nonreciprocity and may pave a route for future rectification devices.
Bibliographical noteKAUST Repository Item: Exported on 2021-02-01
Acknowledged KAUST grant number(s): CRF-2018-3717-CRG7, CRF-2015-SENSORS2708
Acknowledgements: We thank Dr. Keita Hamamoto and Dr. Toshiya Ideue for their useful discussions. We thank Dr. Aitian Chen for the technical support on preparing the devices. The work reported was funded by King Abdullah University of Science and Technology (KAUST), Office of Sponsored Research (OSR) under the Award numbers CRF-2015-SENSORS2708 and CRF-2018-3717-CRG7. This work is also supported by the National Key Research Program of China (grant numbers 2016YFA0300701 and 2017YFB0702702), the National Natural Sciences Foundation of China (Grant numbers 52031015, 1187411, and 51427801), and the Key Research Program of Frontier Sciences, CAS (Grant numbers QYZDJ-SSW-JSC023, KJZD-SW-M01, and ZDYZ2012-2)