Electron-phonon coupling, critical temperatures and gaps in / Ising Superconductors
arXiv:2401.02310 · doi:10.1103/PhysRevB.110.014507
Abstract
Utilizing Migdal-Eliashberg theory of superconductivity within the first-principles calculations, we work out the role of electron-phonon coupling (EPC) and anisotropic superconducting properties of a recently discovered [Appl. Phys. Lett. 120, 183101 (2022)] 2D van der Waals heterostructure comprising a single layer of MoS and few layers of NbSe. We find strong EPC and a softening of phonon modes in the lowest acoustic branch. While the single MoS layer does not actively contribute to the EPC, it significantly elevates the superconducting critical temperature () compared to monolayer NbSe. This is attributed to the degradation of the charge-density wave (CDW) by the MoS layer. Notably, we observe a two-gap superconductivity in / and extend our study to three layers of NbSe. A reduction in with increasing thickness of NbSe is observed. We confirm that this trend is consistent with recent experiments, if one goes beyond three layers of NbSe. We incorporated spin-orbit coupling (SOC) and suggest a possible mechanism for Ising superconductivity. We find that SOC reduces EPC while is suppressed concomitantly by about 5K, leading to a closer estimate of the experimental .
6 figures, Supplementary file attached
References in corpus (12)
- Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
- Advanced capabilities for materials modelling with Quantum ESPRESSO
- Quantum ESPRESSO toward the exascale
- Fermi surface nesting and the origin of Charge Density Waves in metals
- Unusual competition of superconductivity and charge-density-wave state in a compressed topological kagome metal
- Two energy gaps and Fermi surface 'arcs' in NbSe2
- Quasi-Particle Spectra, Charge-Density-Wave, Superconductivity and Electron-Phonon Coupling in 2H-NbSe2
- Quasiparticle Interference, quasiparticle interactions and the origin of the charge density-wave in 2H-NbSe
- Electron-phonon coupling and the Coexistence of Superconductivity and Charge-Density Wave in Monolayer NbSe2
- Enhancement of the upper critical field in disordered transition metal dichalcogenide monolayers
- Electron-phonon superconductivity in CaBi2 and the role of spin-orbit interaction
- Correlated carrier dynamics in a superconducting van der Waals heterostructure