Rashba semiconductor as spin Hall material: Experimental demonstration of spin pumping in wurtzite n-GaN:Si

R. Adhikari, M. Matzer, A. Tarazaga Martín-Luengo, M. C. Scharber, and A. Bonanni
Phys. Rev. B 94, 085205 – Published 31 August 2016
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Abstract

Pure spin currents in semiconductors are essential for implementation in the next generation of spintronic elements. Heterostructures of III-nitride semiconductors are currently employed as central building blocks for lighting and high-power devices. Moreover, the long relaxation times and the spin-orbit coupling (SOC) in these materials indicate them as privileged hosts for spin currents and related phenomena. Spin pumping is an efficient mechanism for the inception of spin current and its conversion into charge current in nonmagnetic metals and semiconductors with Rashba SOC. We report on the generation at room temperature (RT) of pure spin current in nonmagnetic degenerate n-GaN:Si from a magnetic permalloy layer driven to ferromagnetic resonance (FMR) conditions. The FMR signal and the generated Hall voltages due to spin Hall effect, inverse spin Hall effect (ISHE), and spurious mechanisms are detected simultaneously. No spin-pumping-induced voltage could be measured below RT, despite the persistence of FMR signal. After eliminating the spurious (not due to ISHE) components contributing to the generated voltage, we find for n-GaN:Si a spin Hall angle θSH=3.03×103, exceeding by one order of magnitude those reported for other semiconductors, pointing at III-nitrides as particularly efficient spin current generators.

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  • Received 1 April 2016
  • Revised 16 August 2016

DOI:https://doi.org/10.1103/PhysRevB.94.085205

©2016 American Physical Society

Authors & Affiliations

R. Adhikari1,2,*, M. Matzer1,2, A. Tarazaga Martín-Luengo1,2, M. C. Scharber2,3, and A. Bonanni1,2,†

  • 1Institut für Halbleiter-und-Festkörperphysik, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
  • 2Linz Institute of Technology (LIT), Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria
  • 3Linz Institute for Organic Solar Cells, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz, Austria

  • *rajdeep.adhikari@jku.at
  • alberta.bonanni@jku.at

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Issue

Vol. 94, Iss. 8 — 15 August 2016

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