Unconventional pairing in Ising superconductors: Application to monolayer NbSe${}_2$

Abstract

The presence of a non-centrosymmetric crystal structure and in-plane mirror symmetry allows an Ising spin-orbit coupling to form in some two-dimensional materials. Examples include transition metal dichalcogenide superconductors like monolayer NbSe${}_2$, MoS${}_2$, TaS${}_2$, and PbTe${}_2$, where a nontrivial nature of the superconducting state is currently being explored. In this study, we develop a microscopic formalism for Ising superconductors that captures the superconducting instability arising from a momentum-dependent spin- and charge-fluctuation-mediated pairing interaction. We apply our pairing model to the electronic structure of monolayer NbSe${}_2$, where first-principles calculations reveal the presence of strong paramagnetic fluctuations. Our calculations provide a quantitative measure of the mixing between the even- and odd-parity superconducting states and its variation with Coulomb interaction. Further, numerical analysis in the presence of an external Zeeman field reveals the role of Ising spin-orbit coupling and mixing of odd-parity superconducting state in influencing the low-temperature enhancement of the critical magnetic field.

References in corpus (19)

• Valley polarization in MoS2 monolayers by optical pumping
• Valley filter and valley valve in graphene
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Quasi-Particle Spectra, Charge-Density-Wave, Superconductivity and Electron-Phonon Coupling in 2H-NbSe2
• On the Remarkable Superconductivity of FeSe and its Close Cousins
• Superconductivity and Local Inversion-Symmetry Breaking
• Electron-phonon coupling and the Coexistence of Superconductivity and Charge-Density Wave in Monolayer NbSe2
• Crossover of Ising- to Rashba-Type Superconductivity in Epitaxial Bi2Se3/Monolayer NbSe2 Heterostructures
• Enhancement of the upper critical field in disordered transition metal dichalcogenide monolayers
• Superconducting Instabilities in Strongly-Correlated Infinite-Layer Nickelates
• Upper critical field in noncentrosymmetric superconductors
• s+if pairing in Ising superconductors
• Higher angular momentum pairings in interorbital shadowed-triplet superconductors: Application to Sr${}_2$RuO${}_4$
• Quasiparticle energy bands and Fermi surfaces of monolayer NbSe${}_2$
• Weak-Coupling Theory of Pair Density-Wave Instabilities in Transition Metal Dichalcogenides
• Magnetic impurities in thin films and 2D Ising superconductors
• Ising superconductivity: a first-principles perspective
• Higher-order topological superconductivity in monolayer WTe${}_2$ from repulsive interactions
• Ising and XY paramagnons in two-dimensional 2H-NbSe${}_2$

Cited by in corpus (3)

• Friedel oscillations and chiral superconductivity in monolayer NbSe${}_2$
• Unconventional superconductivity in monolayer transition metal dichalcogenides
• Low-temperature anomaly and anisotropy of critical magnetic fields in transition-metal dichalcogenide superconductors