Symposium EQ01: Progress in Thermoelectrics—From Traditional to Novel Materials
December 07, 2022
Eric Toberer, Colorado School of Mines
Defect Design in Thermoelectric Materials—Uniting Computation and Experiment for Tailored Synthesis and Transport Properties
Written by Henry Quansah Afful
The search for application-tailored thermoelectric materials often requires collaborations between experimentalists and computationalists. Eric Toberer points out that for these collaborations to be more fruitful, a deeper understanding of defect phyics is required to calculate native defect energetics and concentrations prior to experiments. This enables more productive efforts at predicting suitable compounds with desired properties. The considerations space in theoretical defect calculations exceed those of experiments. Experiments are mostly limited to nominal stoichiometry and processing parameters, whereas theory considers bandgaps, band masses, and elemental chemical potentials amongst others. This results in scenarios in which expected phase diagrams may differ between the two approaches. Toberer asserts the importance of ensuring not necessarily perfect agreement between the two approaches but rather close enough agreement within the same order of magnitude. This ensures that predicted defect concentrations in different compounds will be close enough to reality. He points out that, in the absence of these defect calculations, defect compensation by antisite defects for similar sites with different charges needs to be critically considered.