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arXiv · 2502.08928

Apparent nonreciprocal transport in FeSe bulk crystals

Taichi Terashima·Shinya Uji·Yuji Matsuda·Takasada Shibauchi·Shigeru Kasahara
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Abstract

We performed low-frequency ac first- and second-harmonic resistance measurements and dc $I-V$ measurements on bulk FeSe crystals in a temperature range between 1.8 and 150 K and in magnetic field up to 14 T. We observed considerable second-harmonic resistance, indicative of nonreciprocal charge transport, in some samples. By examining correlation between contact resistances and second-harmonic signals, we concluded that the second-harmonic resistance was not due to the genuine nonreciprocal transport effect but was caused by joule heating at a current contact through the thermoelectric effect. Our conclusion is consistent with a recent preprint (Nagata \textit{et al.}, arXiv:2409.01715), in which the authors reported a zero-field superconducting diode effect in devices fabricated with FeSe flakes and attributed it to the thermoelectric effect.

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Taichi Terashima, Shinya Uji, Yuji Matsuda, Takasada Shibauchi, Shigeru Kasahara. 2025-02-13. Apparent nonreciprocal transport in FeSe bulk crystals. https://doi.org/10.1103/physrevb.111.054521

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