The spin Hall effect of Bi-Sb alloys driven by thermally excited Dirac-like electrons

Zhendong Chi, Yong Chang Lau, Xiandong Xu, Tadakatsu Ohkubo, Kazuhiro Hono, Masamitsu Hayashi

研究成果: Article

3 引用 (Scopus)

抜粋

We have studied the charge to spin conversion in Bi1−xSbx/CoFeB heterostructures. The spin Hall conductivity (SHC) of the sputter-deposited heterostructures exhibits a high plateau at Bi-rich compositions, corresponding to the topological insulator phase, followed by a decrease of SHC for Sb-richer alloys, in agreement with the calculated intrinsic spin Hall effect of Bi1−xSbx. The SHC increases with increasing Bi1−xSbx thickness before it saturates, indicating that it is the bulk of the alloy that predominantly contributes to the generation of spin current; the topological surface states, if present, play little role. Unexpectedly, the SHC is found to increase with increasing temperature, following the trend of carrier density. These results suggest that the large SHC at room temperature, with a spin Hall efficiency exceeding 1 and an extremely large spin current mobility, is due to increased number of thermally excited Dirac-like electrons in the L valley of the narrow gap Bi1−xSbx alloy.

元の言語English
記事番号eaay2324
ジャーナルScience Advances
6
発行部数10
DOI
出版物ステータスPublished - 2020

ASJC Scopus subject areas

  • General

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