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TT: Fachverband Tiefe Temperaturen

TT 29: Unconventional Superconductors

TT 29.8: Vortrag

Dienstag, 10. März 2026, 11:30–11:45, CHE/0091

Point-contact spectroscopy of atomic contacts from the non-centrosymmetric superconductor Nb₁₈Re₈₂ — •Tiark Tiwary, Elias Hadzic, Marcel Strohmeier, and Elke Scheer — University of Konstanz, 78457 Konstanz, Germany

Revealing various properties of unconventional superconductivity, the non-centrosymmetric superconductor Nb₁₈Re₈₂ (Nb-Re) has become of great interest in the recent years. A key feature is the absence of inversion symmetry which is causing a Rashba-type spin-orbit coupling. Theoretically, this lack of symmetry allows for an admixture of spin-singlet and spin-triplet states. While previous measurements [1] on point contacts with Nb-Re single crystals stated the existance of two distinct BCS-like superconducting energy gaps, measurements on Nb-Re thin films [2] are showing a single s-wave gap. To address these inconsistencies, we utilised the mechanically controlled break junction technique to characterise Nb-Re atomic contacts. We observe the typical features of Andreev refelctions for atomic contacts with high transmission as well as tunneling spectra for contacts with low transmission. As a result the two distinct gaps observed in [1] can be reproduced. While the temperature dependencies of both gaps follow an BCS-like behaviour, the magnetic field dependent measurements shows a non-BCS-like behaviour.
[1] Cirillo et al., Phys. Rev. B, 91, 134508 (2015)
[2] Cirillo et al., Phys. Rev. B, 94, 104512 (2016)

Keywords: Non-centrosymmetric superconductor; Unconventional superconductivity