Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 10: Focus Session: Superconductivity in 2d-Materials and their Heterostructures
TT 10.1: Hauptvortrag
Dienstag, 6. September 2022, 09:30–10:00, H3
Two-fold symmetric superconductivity in few-layer NbSe2 — •Vlad Pribiag — University of Minnesota, USA
Few-layer samples of transition metal dichalcogenides (TMDs) feature a wide array of properties such as layer-dependent inversion symmetry, valley-contrasted Berry curvatures, and strong spin-orbit coupling (SOC). Among the superconducting TMDs, NbSe2 is profoundly affected by Ising SOC. Ising SOC not only helps stabilize the superconducting state against large in-plane magnetic fields, but in conjunction with other forms of SOC, it could also give rise to exotic superconducting states such as nodal topological superconductivity. This talk will discuss recent transport measurements of few-layer NbSe2, and NbSe2/CrBr3 junctions, studied under in-plane external magnetic fields. Surprisingly, although the crystal lattice has a three-fold symmetry, the magneto-resistance and critical field show a two-fold anisotropy, which is absent in the normal state. We will discuss these results in the context of a competition between the conventional s-wave pairing instability characteristic of the bulk and a competing d- or p-wave instability that emerges in the few-layer limit. These results [1] suggest an unconventional character for superconducting pairing in NbSe2 and open the possibility for further discoveries, such as non-trivial topologies, in few-layer TMDs.
[1] A. Hamill et al., Nat. Phys. 17, 949 (2021)