ICT2014 Abstracts

Thermoelectric properties, specifically power factor and thermal conductivity, have been calculated in quantum structures using a Schrodinger model.  The calculations were performed using Greens functions with an effective mass Hamiltonian.  The Green’s functions allow us to calculate true transport with electrical and thermal bias.  More importantly, we can couple phonon and electron transport through self-scattering matrices.   To realize scattering within a wave-type model, we need suitable scattering rates for electron-phonon system as well as the phonon-phonon system.

A method for determining scattering rates needed for Green’s function calculations of thermoelectric properties using molecular dynamics (MD) is developed.  In the current work, the phonon relaxation rates are verified through application of the Landauer formalism, in which the frequency dependent scattering rates are used to determine thermal conductivity.  The approach imposes standing waves corresponding to single phonon modes, which subsequently decay due to anharmonicity in the interatomic potentials. This standing wave approach allows scattering rates and mechanism to be probed more directly than current methods, which include analytic methods using Fermi’s golden rule and other heuristic methods. Results from simulations are presented and compared to published data.