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arXiv · 2501.13577

Emergent spin Hall conductivity in Tantalum-Rhenium alloys

Felix Janus·Jyoti Yadav·Nicolas Beermann·Wentao Zhang·Hassan A. Hafez·Dmitry Turchinovich·Sascha Preu·Markus Meinert
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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.

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Felix Janus, Jyoti Yadav, Nicolas Beermann, Wentao Zhang, Hassan A. Hafez, Dmitry Turchinovich, Sascha Preu, Markus Meinert. 2025-01-23. Emergent spin Hall conductivity in Tantalum-Rhenium alloys. https://doi.org/10.1103/physrevb.111.174411

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