Thermoelectric performance of weakly coupled granular materialsA. Glatz1 and I. S. Beloborodov2
1 Materials Science Division, Argonne National Laboratory - Argonne, IL 60439, USA
2 Department of Physics and Astronomy, California State University Northridge - Northridge, CA 91330, USA
received 7 July 2009; accepted in final form 26 August 2009; published September 2009
published online 24 September 2009
We study thermoelectric properties of inhomogeneous nanogranular materials for weak tunneling conductance between the grains, gt < 1. We calculate the thermopower and figure of merit taking into account the shift of the chemical potential and the asymmetry of the density of states in the vicinity of the Fermi surface. We show that the weak coupling between the grains leads to a high thermopower and low thermal conductivity resulting in relatively high values of the figure of merit on the order of one. We estimate the temperature at which the figure of merit has its maximum value for two- and three-dimensional samples. Our results are applicable for many emerging materials, including artificially self-assembled nanoparticle arrays.
73.63.-b - Electronic transport in nanoscale materials and structures.
72.15.Jf - Thermoelectric and thermomagnetic effects.
73.23.Hk - Coulomb blockade; single electron tunneling.
© EPLA 2009