In this work we present a detailed study and derivation of the thermopower
and thermoelectric coefficient of nano-granular metals at large tunneling
conductance between the grains, g_T>> 1. An important criterion for the
performance of a thermoelectric device is the thermodynamic figure of merit
which is derived using the kinetic coefficients of granular metals. All results
are valid at intermediate temperatures, E_c>>T/g_T>\delta, where \delta is the
mean energy level spacing for a single grain and E_c its charging energy. We
show that the electron-electron interaction leads to an increase of the
thermopower with decreasing grain size and discuss our results in the light of
future generation thermoelectric materials for low temperature applications.
The behavior of the figure of merit depending on system parameters like grain
size, tunneling conductance, and temperature is presented.Comment: 27 pages, 10 figures, revtex
