Estimation of electron-phonon coupling via moving least squares averaging: a method for fast-screening potential thermoelectric materials

Abstract

In this communication, we present a method of predicting the Seebeck coefficient and electrical conductivity of inorganic semiconductors by estimating the electron-phonon (el-ph) coupling from the first principles for fast-screening potential thermoelectric (TE) materials. The method we propose, i.e. the electron-phonon averaged via moving least squares (EPA-MLS) method, combines the EPA method and the MLS averaging strategy. To demonstrate the performance of the EPA-MLS method, the Seebeck coefficient and electrical conductivity of a half-Heusler compound, i.e. HfCoSb, were computed with the EPA-MLS method and compared with the results from the EPA method and comparable experimental data sets. The results show that the EPA-MLS method exhibits several advantages over the original EPA method. The smoother interpolation reduces the risk of spurious numerical behaviors. The EPA-MLS method also requires less human intervention for tuning numerical parameters, since the calculation result of the EPA-MLS method exhibits robustness against the change of associated numerical parameters. The method may even reduce the overall computational cost by allowing the employment of a coarser resolution. All these advantages make the EPA-MLS method a suitable tool for fast-screening potential TE materials. One more example of an archetypical Skutterudite, i.e. CoSb3, is also provided for showing that the method can be used for TE materials with more complex structures.