High-efficiency Pt<sub>75</sub>Au<sub>25</sub>-based spintronic terahertz emitters.

ORAL

Abstract

We demonstrate a new type of STE based on PtxAu100-x alloy that achieves higher THz output power than widely used Pt-based devices. Alloy composition and layer thickness tuning yield Pt75Au25 as the optimal alloy providing a 30% increase in THz power in CoFeB/Pt75Au25 bilayer STEs compared to the optimized CoFeB/Pt reference STE. In W/CoFeB/Pt75Au25 trilayer STEs, we observe a 10% higher THz power than in the optimized W/CoFeB/Pt trilayer. The STE efficiency is reduced upon annealing for both Pt75Au25- and Pt-based STEs due to formation of interfacial alloys. Our results establish Pt75Au25 as a promising platform for high-performance STEs, where its giant spin Hall effect significantly enhances efficiency over conventional Pt-based devices.

*This work was primarily supported by the National Science Foundation Materials Research Science and Engineering Center program through the UC Irvine Center for Complex and Active Materials (DMR-2011967). THz detection setup development was supported by the Office of Basic Energy Sciences of the U.S. Department of Energy Award Number DE-SC0024037. Partial support from the National Science Foundation via awards ECCS-2213690 and DMREF-2324203 as well as from the University of California National Laboratory Fees Research Program is also acknowledged. We also thank the Eddleman Quantum Institute (EQI) for providing materials and supplies. The authors acknowledge the use of facilities and instrumentation at the UC Irvine Materials Research Institute (IMRI), which is supported in part by the National Science Foundation through the UC Irvine Materials Research Science and Engineering Center (DMR-2011967).

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Publication: W. Shi, G. D. Nelson, H.-H. Wu, Y. Ju, X. Pan, W. Ho, and I. N. Krivorotov, "High-efficiency Pt₇₅Au₂₅-based spintronic terahertz emitters," arXiv:2509.25303 [cond-mat.mtrl-sci] (2025).

Presenters

  • Gene David Nelson

    • University of California, Irvine

Authors

  • Gene David Nelson

    • University of California, Irvine

  • Wenlu Shi

    • University of California, Irvine

  • Han-Hsuan Wu

    • University of California Irvine

  • Yiwei Ju

    • University of California Irvine

  • Xiaoqing Pan

    • University of California, Irvine

  • Wilson Ho

    • University of California, Irvine

  • Ilya N Krivorotov

    • University of California, Irvine