Gap structure in noncentrosymmetric superconductors

Abstract

Gap structure in noncentrosymmetric superconductors with spin-orbit band splitting is studied using a microscopic model of pairing mediated by phonons and/or spin fluctuations. The general form of pairing interaction in the band representation is derived, which includes both the intraband and interband pairing terms. In the case of isotropic interaction (in particular, for a BCS-contact interaction), the interband pairing terms vanish identically at any magnitude of the band splitting. The effects of pairing interaction anisotropy are analyzed in detail for a metal of cubic symmetry with strong spin-orbit coupling. It is shown that if phonons are dominant then the gaps in two bands are isotropic, nodeless, and have in general different amplitudes. Applications to the Li_2(Pd_{1-x},Pt_x)_3B family of noncentrosymmetric superconductors are discussed.

9 pages; minor corrections, published version

References in corpus (5)

• Spin Triplet Superconducting State due to Broken Inversion Symmetry in Li_2Pt_3B
• Order parameter in superconductors with non-degenerate bands
• Crystal Symmetry, Electron-Phonon Coupling, and Superconducting Tendencies in Li${}_2$Pd${}_3$B and Li${}_2$Pt${}_3$B
• On the spin susceptibility of noncentrosymmetric superconductors
• Effects of impurities on superconductivity in noncentrosymmetric compounds

Cited by in corpus (6)

• Evidence for time-reversal symmetry breaking in the non-centrosymmetric superconductor LaNiC${}_2$
• Nonuniform states in noncentrosymmetric superconductors
• Upper critical field in noncentrosymmetric superconductors
• Superconducting state in the non-centrosymmetric Mg_{9.3}Ir_{19}B_{16.7} and Mg_{10.5}Ir_{19}B_{17.1} revealed by NMR
• Electronic Raman scattering in non-centrosymmetric superconductors
• Effects of impurities on Hc2(T) in superconductors without inversion symmetry