Spin to Charge Current Conversion in the Topological Insulator (Bi<sub>0.22</sub>Sb<sub>0.78</sub>)<sub>2</sub>Te<sub>3 </sub>Films at Room Temperature
POSTER
Abstract
Topological Insulators (TIs) constitute a new class of quantum materials, and here we report spin to charge current conversion in an intrinsic TI (Bi0.22Sb0.78)2Te3 film at room temperature. The spin currents are generated in a thin layer of permalloy (Py) by two different processes, spin pumping effect (SPE) and spin Seebeck effect (SSE). In the first process, we use microwave-driven ferromagnetic resonance of the Py film to generate a SPE spin current that is injected into the TI (Bi0.22Sb0.78)2Te3 layer in direct contact with Py. In the second process, we use the SSE in the longitudinal configuration in Py without contamination by the Nernst effect made possible with the use of a thin NiO layer between the Py and (Bi0.22Sb0.78)2Te3 layers. The spin-to-charge current conversion is attributed to the inverse Edelstein effect (IEE) by the spin-momentum locking in the electron Fermi contours due to the Rashba field. The measurements by the two techniques yield very similar values for the IEE parameter, which are larger than the reported values in the previous studies on TIs.
*Research supported in Brazil by the agencies CNPq, CAPES, FINEP, FAPEMIG, FACEPE, and in USA by the STC-CIQM under NSF grant DMR-1231319, NSF (DMR-1207469, DMR-1700137), ONR (N00014-13-1-0301, N00014-16-1-2657).
Presenters
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Joaquim Mendes
- Departamento de Física, Universidade Federal de Viçosa