Quantum Simulation of Nanocrystalline Composite Thermoelectric Properties

For the past few years, nanoscale structures have been proposed and investigated experimentally for their enhanced thermoelectric properties over bulk materials. These structures offer several advantages: 1) increased local density of states, which can improve the Seebeck coefficient and 2) reduced thermal transport due to phonon confinement and increased scattering. Recently, nanocrystalline composites (NCC) have been examined for their ability to outperform the alloy limit in terms of reduced thermal conductivity. However, the electrical performance has not been examined from a quantum point of view. This work provides quantum simulations of a two-dimensional composite system meant to model certain geometric features of NCC’s. While the results cannot be quantitatively compared to actual measurements, they show how their electrical behavior differs from well-known superlattice devices. This work will aid in the design of the next generation of NCC devices for thermoelectric performance. NOMENCLATURE d Diameter (nm) l Length (nm) T Temperature (K) S Seebeck (μ V/K) σ Electrical Conductivity (1/Ω-m) PF Power Factor (W/m2K) ZT Thermoelectric Figure of Merit Address all correspondence to this author. k Thermal Conductivity (W/m2K)