Nonunitary triplet pairing in the noncentorsymmetric superconductor LaNiC₂

In muon spin-relaxation experiments the noncentorsymmetric superconductor LaNiC₂ showed that on entering the superconducting state it also breaks time-reversal symmetry [1]. Based on group theoretical considerations it was already shown that the breaking of time-reversal symmetry is only compatible with nonunitary triplet pairing states [2,3]. To investigate the pairing mechanism by which this comes about and the possible role that the lack of inversion symmetry, we have generalized the relativistic spin-polarized version of Korringa-Kohn-Rostoker method for the solution of the Dirac-Bogoliubov-de Gennes equations [4]. Based on a particularly efficient parametrization of the pairing interaction afforded by the density-functional theory for superconductors different orbital-selective pairing models have been studied in quantitative detail.


[1] A. D. Hillier, J. Quintanilla, and R. Cywinski, Phys. Rev. Lett. 102, 117007 (2009)

[2] Jorge Quintanilla, Adrian D. Hillier, James F. Annett, and R. Cywinski, Phys. Rev. B 82, 174511 (2010)

[3] A. D. Hillier, J. Quintanilla, B. Mazidian, J. F. Annett, and R. Cywinski, Phys. Rev. Lett. 109, 097001 (2012)

[4] Gabor Csire, Balazs Ujfalussy, Jozsef Cserti, and Balazs Gyorffy, Phys. Rev. B 91, 165142 (2015)