Emergent spin Hall conductivity in Tantalum-Rhenium alloys

Abstract

We investigate the spin Hall conductivity (SHC) of a composition series of a Ta-Re bcc solid solution. At approximately 60 at.% Ta the Ta-Re alloy features an SHC similar to bcc-W, while both endpoints of the compositional series have rather moderate SHC. The intermediate stoichiometries exhibit a substantial enhancement due to Fermi level tuning through the same band structure feature which gives bcc-W and $\beta$-W its large SHC. We provide experimental evidence for the enhancement of the SHC in the alloy via THz emission upon ultrafast laser excitation of Ta-Re/CoFeB bilayers. We demonstrate that a rigid band model derived from bcc-W and Fermi level tuning describes the experimental data with a similar accuracy as coherent potential approximation alloy calculations of the SHC.

8 pages, 5 figures

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• Study of Intrinsic Spin Hall Effect and Orbital Hall Effect in 4d- and 5d- Transition Metals
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Cited by in corpus (1)

• High-efficiency Pt${}_{75}$Au${}_{25}$-based spintronic terahertz emitters