Specific heat and thermal conductivity in Sr₂RuO₄ for rotating in-plane magnetic field

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We calculate the density of states N and the the thermal conductivity κ in layered superconductors for rotating in-plane magnetic field by using approximate analytical expressions for Abrikosov's vortex lattice state. For a gap with dxy - orbital symmetry we find that the differences ΔN and Δκ between field directions parallel to the antinodes and parallel to the nodes of the gap are positive for lower fields and change sign for higher fields near Hc₂. For increasing impurity scattering, ΔN and Δκ decrease due to a broadening of certain peaks in the angle-resolved density of states. The frequency dependencies of the amplitudes ΔN and Δκ exhibit similar crossover behavior at low frequencies which give rise to a sign change of Δκ at low T/Tc. We conclude that variations of the specific heat and thermal conductivity can be observed only in the clean and low temperature limits.