Lower Critical Field Hc1(T) and Pairing Symmetry Based on Eilenberger Theory

We quantitatively estimate different T-dependences of Hc1 between s wave and d wave pairings by Eilenberger theory. The T-dependences of Hc1(T) show quantitative deviation from those in London theory. We also study differences of Hc1(T) between p+ and p- wave pairing in chiral p wave superconductors. There, Hc1(T) is lower in p- wave pairing, and shows the same T-dependence as in s wave pairing.Comment: 2 pages, 1 figur

Relation between Vortex Excitation and Thermal Conductivity in Superconductors

Thermal conductivity $\kappa_{xx}(T)$ under a field is investigated in $d_{x^2-y^2}$-wave superconductors and isotropic s-wave superconductors by the linear response theory, using a microscopic wave function of the vortex lattice states. To study the origin of the different field dependence of $\kappa_{xx}(T)$ between higher and lower temperature regions, we analyze the spatially-resolved thermal conductivity around a vortex at each temperature, which is related to the spectrum of the local density of states. We also discuss the electric conductivity in the same formulation for a comparison.Comment: 9 pages, 11 figures, to appear in European Physical Journal

NMR relaxation time around a vortex in stripe superconductors

Site-dependent NMR relaxation time $T_1({\bf r})$ is calculated in the vortex state using the Bogoliubov-de Gennes theory, taking account of possible "field-induced stripe'' states in which the magnetism arises locally around a vortex core in d-wave superconductivity. The recently observed huge enhancement $T_1^{-1}({\bf r})$ below $T_c$ at a core site in Tl$_2$Ba$_2$CuO$_6$ is explained. The field-induced stripe picture explains consistently other relevant STM and neutron experiments.Comment: 4 pages, 4 figure