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arXiv · 2210.06912

Interface superconductivity in a type-II Dirac semimetal NiTe$_2$

V. D. Esin·O. O. Shvetsov·A. V. Timonina·N. N. Kolesnikov·E. V. Deviatov
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Abstract

We experimentally investigate charge transport through a single planar junction between a NiTe$_2$ Dirac semimetal and a normal gold lead. At millikelvin temperatures we observe non-Ohmic $dV/dI(V)$ behavior resembling Andreev reflection at a superconductor -- normal metal interface, while NiTe$_2$ bulk remains non-superconducting. The conclusion on superconductivity is also supported by suppression of the effect by temperature and magnetic field. In analogy with the known results for Cd$_3$As$_2$ Dirac semimetal, we connect this behavior with interfacial superconductivity due to the flat-band formation at the Au-NiTe$_2$ interface. Since the flat-band and topological surface states are closely connected, the claim on the flat-band-induced superconductivity is also supported by the Josephson current through the topological surface states on the pristine NiTe$_2$ surface. We demonstrate the pronounced Josephson diode effect, which results from the momentum shift of topological surface states of NiTe$_2$ under an in-plane magnetic field.

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V. D. Esin, O. O. Shvetsov, A. V. Timonina, N. N. Kolesnikov, E. V. Deviatov. 2022-10-13. Interface superconductivity in a type-II Dirac semimetal NiTe$_2$. https://doi.org/10.3390/nano12234114

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