The magnetic field dependence of low temperature specific heat in YNi2B2C was measured and analyzed using various pairing order parameters. At zero magnetic field, the two-gap model which has been successfully applied to MgB2 and the point-node model, appear to describe the superconducting gap function of YNi2B2C better than other models based on the isotropic s-wave, the d-wave line nodes, or the s+g wave. The two energy gaps, delta_L=2.67 meV and delta_S=1.19 meV are obtained. The observed nonlinear field dependence of electronic specific heat coefficient, gamma(H)~H0.47, is quantitatively close to gamma(H)~H0.5 expected for nodal superconductivity or can be qualitatively explained using two-gap scenario. Furthermore, the positive curvature in Hc2(T) near Tc is qualitatively similar to that in the other two-gap superconductor MgB2.
@article{arxiv.cond-mat/0512291,
title = {Comparative analysis of specific heat of YNi2B2C using nodal and two-gap models},
author = {C. L. Huang and J. Y. Lin and C. P. Sun and T. K. Lee and J. D. Kim and E. M. Choi and S. I. Lee and H. D. Yang},
journal= {arXiv preprint arXiv:cond-mat/0512291},
year = {2009}
}
Comments
4 pages, 5 figures, to be published in Physical Review B