Ising and XY paramagnons in two-dimensional 2H-NbSe
arXiv:2110.09809 · doi:10.1103/PhysRevB.105.224412
Abstract
Paramagnons are the collective modes that govern the spin response of nearly magnetic conductors. In some cases they mediate electron pairing leading to superconductivity. This scenario may occur in 2H-NbSe monolayers, that feature spin-valley coupling on account of spin-orbit interactions and their lack of inversion symmetry. Here we explore spin anisotropy of paramagnons both for non-centrosymmetric Kane-Mele-Hubbard models for 2H-NbSe monolayers described with a DFT-derived tight-binding model. In the infinite wavelength limit we find spatially uniform paramagnons with energies around ~meV that feature a colossal off-plane uniaxial magnetic anisotropy, with quenched transversal spin response. At finite wave vectors, longitudinal and transverse channels reverse roles: XY fluctuations dominate within a significant portion of the Brillouin zone. Our results show that 2H-NbSe is close to a Coulomb-driven in-plane (XY) spin density wave instability.
arXiv comment10 pages (6 main text, 4 supplementary material), 10 figures (4 in the main text, 6 in the SM)
References in corpus (24)
- Magic-angle graphene superlattices: a new platform for unconventional superconductivity
- Quantum Spin Hall Effect in Graphene
- Advanced capabilities for materials modelling with Quantum ESPRESSO
- Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
- Spontaneously polarized half-gapped superconductivity
- Large spin splitting in the conduction band of transition metal dichalcogenide monolayers
- Topological Superconductivity in Twisted Multilayer Graphene
- Superconductivity in rhombohedral trilayer graphene
- Topological Insulators and Mott Physics from the Hubbard Interaction
- Superconductivity from Valley Fluctuations and Approximate SO(4) Symmetry in a Weak Coupling Theory of Twisted Bilayer Graphene
- Unexpected two-fold symmetric superconductivity in few-layer NbSe
- Spin-Polarized Electrons in Monolayer MoS
- Knight Shift and Leading Superconducting Instability From Spin Fluctuations in Sr2RuO4
- Spin Orbit Coupling and Spin Waves in Ultrathin Ferromagnets: The Spin Wave Rashba Effect
- Effective and accurate representation of extended Bloch states on finite Hilbert spaces
- Ising superconductivity and magnetism in NbSe
- Spontaneous persistent currents in magnetically ordered graphene ribbons
- Direct observation of paramagnons in palladium
- Unconventional superconductivity in a doped quantum spin Hall insulator
- Confinement-engineered superconductor to correlated-insulator transition in a van der Waals monolayer
- A unified theory of spin and charge excitations in high- cuprates: Quantitative comparison with experiment and interpretation
- Superconducting phase diagram of itinerant antiferromagnets
- Robust spin and charge excitations throughout high--cuprate phase diagram from incipient Mottness
- Pairing mechanism of unconventional superconductivity in doped Kane-Mele model