BALLISTIC LANDAUER-TYPE THERMAL-CONDUCTIVITY OF A DIELECTRIC POINT-CONTACT

The contribution of the phonon diffraction effects to the thermal cond uctivity of dielectric and metal-dielectric point contacts is investig ated. A formula analogous to the Landauer formula for electron conduct ivity holds for the thermal conductivity of the contact. Measurements of the heat flux of Si-Cu point contacts reveal a well-defined diffrac tion maxima of reduced thermal conductivity of the point contacts at t emperatures 0.5-1 K.