  An asymmetry as a function of the direction of current flow is observed in
the current-voltage characteristic (CVC) and its first and second derivatives
for point heterocontacts between pure metals {Cu, Ni, Fe) as well as between
these metals and dilute alloys (CuFe, CuMn). It is shown that the observed
asymmetry is caused by thermoelectrical phenomena (Seebeck, Peltier, and
Thompson effects), observed when the temperature inside the contact differs
from the temperature of the bath. In the low energy range (less than or of the
order of the Debye energy) the asymmetry of the CVC is affected mainly by the
Seebeck effect, while at high energies and for larger contacts (lower
resistance) the contributions of all noted effects are of the same order of
magnitude. A technique is proposed for determining the temperature of a
heterocontact by measuring the CVC in two polarities. It is established that in
the intermediate (between the diffusion and ballistic) state of flight of the
electrons through the constriction the temperature of the heterocontact
increases linearly with the voltage on it, and all the more rapidly the larger
the contact and the more impurity in it.
