Tailoring FeSi Single Crystals: Influence of Sn, Te, and Ga Flux on Morphology and Electrical Resistance

ORAL

Abstract

Recent studies of the d-electron narrow gap semiconductor FeSi revealed the presence of a conducting surface state and a ferromagnetic surface state [1, 2], suggesting that FeSi could be a candidate for a topological Kondo insulator. Previous electrical resistivity measurements have shown strong sample dependence, emphasizing the need to explore synthesis conditions to ensure reproducibility and consistency in producing high quality FeSi single crystals. Motivated by this issue, we synthesized and characterized FeSi single crystals using various molten metal fluxes, including Sn, Te, and Ga. The type of flux significantly influenced the morphology, yielding crystals shaped like needles, triangular prisms, and polyhedra for Sn, Te, and Ga, respectively. Laue and X-ray diffraction confirmed pure FeSi phase and consistent lattice parameters across all samples. Resistivity measurements revealed two distinct Arrhenius-like regions below 200 K for Sn- and Te-flux grown FeSi, while Ga-flux-grown FeSi showed only one. Additionally, the resistivity exhibited a peak at 20 K for Sn-flux, 5 K for Te-flux, and 30 K for Ga-flux.

*AcknowledgmentsResearch at the University of California San Diego was supported by the U.S. Department of Energy (DOE) Basic Energy Sciences under Grant DE-FG02-04ER46105 and the National Nuclear Security Administration under the Stewardship Science Academic Alliance Program through the US DOE under Grant No. DE-NA0004086.

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Publication: References
[1] Fang, Yuankan, et al., Proceedings of the National Academy of Sciences 115 (34), 8558 (2018).
[2] Ohtsuka, Yusuke, et al., Science Advances 7, eabj0498 (2021).

Presenters

  • Keke Feng

    • Department of Physics, University of California, San Diego
    • University of California, San Diego
    • University of California San Diego

Authors

  • Keke Feng

    • Department of Physics, University of California, San Diego
    • University of California, San Diego
    • University of California San Diego

  • Caleb Robinson

    • University of California, San Diego

  • Tyler Woods Wannamaker

    • University of California San Diego

  • Gabriel Mercado

    • University of California, San Diego
    • University of California San Diego

  • Eric Lee-Wong

    • University of California San Diego

  • Yuhang Deng

    • University of California, San Diego
    • Department of Physics, University of California, San Diego, CA 92093, USA

  • Weiwei Xie

    • Rutgers University

  • M. Brian Maple

    • University of California, San Diego
    • University of California San Diego
    • Department of Physics, University of California, San Diego, CA 92093, USA