We study the electron thermal transport in granular metals at large tunnel conductance between the grains, gT≫1 and not too low a temperature T>gTδ, where δ is the mean energy level spacing for a single grain. Taking into account the electron-electron interaction effects we calculate the thermal conductivity and show that the Wiedemann-Franz law is violated for granular metals. We find that interaction effects suppress the thermal conductivity less than the electrical conductivity.
@article{arxiv.cond-mat/0402190,
title = {Thermal transport in granular metals},
author = {I. S. Beloborodov and A. V. Lopatin and F. W. J. Hekking and Rosario Fazio and V. M. Vinokur},
journal= {arXiv preprint arXiv:cond-mat/0402190},
year = {2009}
}