Wiedemann–Franz law in proximity bilayers Original Research Article

Wiedemann–Franz law in the diffusive normal metal/insulator/d-wave superconductor junctions is studied for various transparency of the insulating barrier and various misorientation angles between the normal to the interface and the crystal axis of d-wave superconductors. Contrary to the conductance, the thermal conductance of the junctions does not depend seriously on the misorientation angle α of the junctions. Reflecting the formation of the midgap Andreev resonant states at the junction interface, the temperature dependence of the Lorentz ratio depends drastically on α for low transparent junctions.