Impurity effects on s+g-wave superconductivity in borocarbides Y(Lu)Ni_2B_2C

Abstract

Recently a hybrid s+g-wave pairing is proposed to describe the experimental observation for a nodal structure of the superconducting gap in borocarbide YNi${}_2$B${}_2$C and possibly LuNi${}_2$B${}_2$C. In this paper the impurity effects on the s+g-wave superconductivity are studied in both Born and unitarity limit. The quasiparticle density of states and thermodynamics are calculated. It is found that the nodal excitations in the clean system are immediately prohibited by impurity scattering and a finite energy gap increases quickly with the impurity scattering rate. This leads to an activated behavior in the temperature dependence of the specific heat. Qualitative agreement with the experimental results is shown. Comparison with d-wave and some anisotropic s-wave studied previously is also made.

arXiv comment6 pages, 6 eps figures

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Cited by in corpus (7)

• Comparative analysis of specific heat of YNi2B2C using nodal and two-gap models
• Triplet superconductivity in the skutterudite PrOs_4Sb_12
• Quasiparticle spectrum of the hybrid s+g-wave superconductors YNi_2B_2C and LuNi_2B_2C
• Superconducting order parameter in nonmagnetic borocarbides RNi${}_2$B${}_2$C (R=Y, Lu) probed by point-contact Andreev reflection spectroscopy
• Superconductivity and Antiferromagnetism in Quasi-one-dimensional Organic Conductors
• Evolution of ground state and upper critical field in R(1-x)GdxNi2B2C (R = Lu, Y): Coexistence of superconductivity and spin-glass state
• Disorder-driven superconductor-normal metal phase transition in quasi-one-dimensional organic conductors