Thermal transport in granular metalsI. S. Beloborodov1, A. V. Lopatin1, F. W. J. Hekking2, Rosario Fazio3 and V. M. Vinokur1
1 Materials Science Division, Argonne National Laboratory - Argonne, IL 60439, USA
2 Laboratoire de Physique et Modélisation des Milieux Condensés CNRS and Université Joseph Fourier - BP 166, 38042 Grenoble-cedex 9, France
3 NEST-INFM and Scuola Normale Superiore - I-56126 Pisa, Italy
received 27 August 2004; accepted in final form 19 November 2004
published online 24 December 2004
We study the electron thermal transport in granular metals at large tunnel conductance between the grains, , and not too low a temperature, , where 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.
73.23.Hk - Coulomb blockade; single-electron tunneling.
73.22.Lp - Collective excitations.
72.15.Jf - Thermoelectric and thermomagnetic effects.
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