ab initio Electronic Transport Model with Explicit Solution to the Linearized Boltzmann Transport Equation

摘要

Accurate models of carrier transport are essential for describing theelectronic properties of semiconductor materials. To the best of our knowledge,the current models following the framework of the Boltzmann transport equation(BTE) either rely heavily on experimental data (i.e., semi-empirical), orutilize simplifying assumptions, such as the constant relaxation timeapproximation (BTE-cRTA). While these models offer valuable physical insightsand accurate calculations of transport properties in some cases, they oftenlack sufficient accuracy -- particularly in capturing the correct trends withtemperature and carrier concentration. We present here a general transportmodel for calculating low-field electrical drift mobility and Seebeckcoefficient of n-type semiconductors, by explicitly considering all relevantphysical phenomena (i.e. elastic and inelastic scattering mechanisms). We firstrewrite expressions for the rates of elastic scattering mechanisms, in terms ofab initio properties, such as the band structure, density of states, and polaroptical phonon frequency. We then solve the linear BTE to obtain theperturbation to the electron distribution -- resulting from the dominantscattering mechanisms -- and use this to calculate the overall mobility andSeebeck coefficient. Using our model, we accurately calculate electricaltransport properties of the compound n-type semiconductors, GaAs and InN, overvarious ranges of temperature and carrier concentration. Our fully predictivemodel provides high accuracy when compared to experimental measurements on bothGaAs and InN, and vastly outperforms both semi-empirical models and theBTE-cRTA. Therefore, we assert that this approach represents a first steptowards a fully ab initio carrier transport model that is valid in all compoundsemiconductors.