Spin-orbit assisted superconductivity in transition metal dichalcogenides

by Prof. Maxim Khodas

Faculty of Mathematics and Sciences,HUJI

at Condensed Matter Seminar

Mon, 12 Feb 2024, 11:10
Sacta-Rashi Building for Physics (54), room 207

Abstract

Mono- and few-layer transition metal dichalcogenides (TMDs) are two-dimensional superconductors with the transition temperature of a few Kelvins.
These superconductors have an extremely anisotropic critical magnetic field with the parallel critical field far above the Pauli limit.
The mono-layer TMDs are non-centrosymmetric with strong spin-orbit interaction polarizing spins out-of-plane.
The spin-orbit interaction protects the conventional spin-singlet superconductivity against the pair breaking by the magnetic field.
We argue that in addition, the spin-orbit interaction mediates the transformation of singlet Cooper pairs into the triplet Cooper pairs by the applied field.
These parallel spin triplets are distinct from the anti-parallel spin triplets present at zero magnetic field.
Since the parallel spin triplets are field induced, they have a strong effect on the critical field.
Besides, these spin triplets are protected against the disorder scattering thanks to their strong coupling with the spin singlets.
In recent experiments two-fold transport anisotropies have been reported inconsistent with the hexagonal symmetry of the underlying lattice.
We list possible scenarios of the two-fold symmetry based on pairing of conventional as well as unconventional symmetry.
Finally, I discuss the manifestations of the field induced topological phase transition in the 4 periodic current phase relation of the TMD based planar Josephson junctions.

Created on 07-02-2024 by Naamneh, Muntaser (mnaamneh)
Updaded on 08-02-2024 by Naamneh, Muntaser (mnaamneh)