We present a theory for the thermopower observed in scanning tunneling microscopy. The lateral variation of the thermopower is found to depend on the logarithmic derivative of the local sample density of states at the Fermi level. We also derive a relation between the thermopower and the nonlinear conductance. The heat transfer due to the tunneling electrons obeys the Wiedemann-Franz law.

• Received 5 June 1990

DOI:https://doi.org/10.1103/PhysRevB.42.9214