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

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.

References in corpus (9)

• Intrinsic Superconducting Diode Effect
• Supercurrent diode effect and finite momentum superconductivity
• A phenomenological theory of superconductor diodes
• Band geometry, Berry curvature and superfluid weight
• Strain-induced partially flat band, helical snake states, and interface superconductivity in topological crystalline insulators
• Dimensional crossover in topological matter: Evolution of the multiple Dirac point in the layered system to the flat band on the surface
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• Josephson spin-valve realization in the magnetic nodal-line topological semimetal Fe${}_3$GeTe${}_2$
• Conductance oscillations and zero-bias anomaly in a single superconducting junction to a three-dimensional $B{i}_{2}T{e}_3$ topological insulator

Cited by in corpus (7)

• Intrinsic surface superconducting instability in Type-I Weyl Semimetals
• Gate-dependent non-linear Hall effect at room temperature in topological semimetal GeTe
• Andreev reflection for MnTe altermagnet candidate
• Magnetic field filtering of the hinge supercurrent in unconventional metal NiTe${}_2$-based Josephson junctions
• Reentrant proximity-induced superconductivity for GeTe semimetal
• Josephson diode and spin-valve effects on the surface of altermagnet CrSb
• Fractional ac Josephson effect as evidence of topological hinge states in a Dirac semimetal NiTe2