Quantitative theory of triplet pairing in the unconventional superconductor LaNiGa2

The exceptionally low-symmetry crystal structures of the time-reversal symmetry-breaking superconductors LaNiC2 and LaNiGa2 lead to an internally antisymmetric nonunitary triplet state as the only possibility compatible with experiments. We argue that this state has a distinct signature: A double-pe...

Descripción completa

Detalles Bibliográficos
Autores: Ghosh, Sudeep Kumar|||0000-0002-3646-0629, Csire, Gabor|||0000-0002-3745-8694, Whittlesea, Philip, Annett, James|||0000-0002-2361-2443, Gradhand, Martin, Újfalussy, Balázs, Quintanilla, Jorge
Tipo de recurso: artículo
Fecha de publicación:2020
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:230705
Acceso en línea:https://ddd.uab.cat/record/230705
https://dx.doi.org/urn:doi:10.1103/PhysRevB.101.100506
Access Level:acceso abierto
Palabra clave:Adjustable parameters
Critical temperatures
Electronic band structure
Electronic specific heat
Low symmetry crystals
Superconducting state
Time reversal symmetries
Unconventional superconductors
Descripción
Sumario:The exceptionally low-symmetry crystal structures of the time-reversal symmetry-breaking superconductors LaNiC2 and LaNiGa2 lead to an internally antisymmetric nonunitary triplet state as the only possibility compatible with experiments. We argue that this state has a distinct signature: A double-peak structure in the density of states (DOS) which resolves in the spin channel in a particular way. We construct a detailed model of LaNiGa2 capturing its electronic band structure and magnetic properties ab initio. The pairing mechanism is described via a single adjustable parameter. The latter is fixed by the critical temperature Tc allowing parameter-free predictions. We compute the electronic specific heat and find excellent agreement with experiment. The size of the ordered moment in the superconducting state is compatible with zero-field muon spin relaxation experiments and the predicted spin-resolved DOS suggests the spin splitting is within the reach of present experimental technology.