Nodal structure of quasi-two-dimensional superconductors probed by a magnetic field.
We consider a quasi-two-dimensional superconductor with line nodes in the presence of an in-plane magnetic field, and compute the dependence of the specific heat C and the in-plane heat conductivity kappa on the angle between the field and the nodal direction in the vortex state. We use a variation of the microscopic Brandt-Pesch-Tewordt method that accounts for the scattering of quasiparticles off vortices, and analyze the signature of the nodes in C and kappa. At low to moderate fields the specific heat anisotropy changes sign with increasing temperature. Comparison with measurements of C and kappa in CeCoIn(5) resolves the contradiction between the two in favor of the d((x(2)-y(2)) gap.
Vorontsov
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Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
Vekhter
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