Thermo-Coulomb effects in mesoseopic tunnel junctions

We present a study of the thermoelectric effects in tunnel junctions. In particular we calculate the thermopower coefficient S and the Peltier coefficient H. For macroscopic junctions we demonstrate the sensitivity of S and H to the structure of the density of states. For mesoscopic junctions we show that Coulomb effects modify the ordinary Onsager picture and the relation H = TS. The coefficients S and H are found to be very sensitive to the coupling of the junctions to the external world, We analyze measurements of the thermopower in granular films in terms of the thermo-Coulomb effects. We comment on the relevance of these effects to scanning tunneling microscope measurements.