F.Yu, V.N. Kopylov, M.B. Salamon, N.N. Kolesnikov, M.A. Hubbard, H.M. Duan, A.M. Hermann.
Field dependent thermal conductivity of Tl₂Ba₂CuO₆: evidence for Andreev scattering of quasiparticles.

  Abstract:
We have studied the thermal conductivity of  Tl₂Ba₂CuO₆   (Tl-2201) crystals as functions of temperature  and magnetic field. A thermal conductivity peak is observed near 0.6 T_c which is greatly reduced on application of a magnetic field along the c axis. We argue that the suppression of the peak at relatively low fields (£ 8 T<< H_c2) permits us to separate electronic and phononic contributions. Fields applied in plane are less effective, but give the same reduction when applied either parallel or perpendicular to the temperature gradient. A model based on Andreev reflection by vortex screening currents is shown to be consistent with these results.