Thermal conductance of metallic point contacts
Аннотация
Measurements have been carried out between 4.2 and 140° K of the heat flux Q across Au–Au point contacts. A purely electronic mechanism for heat flow across a mechanical contact between two metal electrodes has been realized for the first time. It is shown that the temperature dependence Q(T) for T ≥ 25−30° K is determined by the relation between the electron mean free path, l, and the diameter of the point contact, d, approaching quadratic as 1/d is increased. Measurements of Q(T) and RV(T) enable the temperature dependence of the Lorenz number to be determined for a microcontact and also to estimate its diameter.