This talk will discuss our recent work on using first-principles simulations to investigate both electron and phonon thermoelectric transport in silicon. Electron-phonon and electron-impurity scatterings are computed from first principles calculations to obtain electron relaxation times due to both phonon and impurity scattering. The energy dependent relaxation times are then used in the Boltzmann transport theory to obtain the electrical conductivity, Seebeck coefficient and electronic thermal conductivity. The anharmonic force constants are derived from first-principles and used to compute phonon relaxation times based on Fermi’s golden rule. The energy dependent mean free paths are computed for both electrons and phonons. The electrical and thermal conductivity accumulation functions in silicon with respect to electron and phonon mean free paths are compared. The electron-filtering concept is examined using our energy dependent transport data. It demonstrates the capability to quantitatively investigate various electron engineering approaches. By combining all electron and phonon transport properties from first-principles, we predict the full thermoelectric properties of the bulk and nanostructure of silicon over a range of temperatures from 100 to 400 K and doping levels from to cm-3, showing good agreement with experiments. This work is supported by S3TEC, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number: DE-SC0001299/DE-FG02-09ER46577.
Head of the Department of Mechanical Engineering and Carl Richard Soderberg Professor of Power Engineering,
Massachusetts Institute of Technology
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