We calculate the density of states $N$ and the the thermal conductivity$\kappa $ in layered superconductors for rotating in-plane magnetic field byusing approximate analytical expressions for Abrikosov's vortex lattice state.For a gap with d$_{xy} $- orbital symmetry we find that the differences $\DeltaN$ and $\Delta\kappa$ between field directions parallel to the antinodes andparallel to the nodes of the gap are positive for lower fields and change signfor higher fields near $H_{c2} $. For increasing impurity scattering, $\DeltaN$ and $\Delta\kappa$ decrease due to a broadening of certain peaks in theangle-resolved density of states. The frequency dependencies of the amplitudes$\Delta N$ and $\Delta\kappa$ exhibit similar crossover behavior at lowfrequencies which give rise to a sign change of $\Delta\kappa$ at low $T/T_c $.We conclude that variations of the specific heat and thermal conductivity canbe observed only in the clean and low temperature limits.
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