Engineering Chemical Environments for Efficient Thermoelectric and Heat Transport Materials using First-principles Calculation

Abstract

To optimize the management of heat generated in various industrial processes, it is imperative to utilize materials that can proficiently transport heat energy and convert it into valuable electrical power. Conversion of heat to electrical energy can be done using thermoelectric materials. Designing such materials is very challenging as it involves complex interdependence among electronic and thermal transport parameters, which depends upon the structural, physical, and chemical features of the material. Here, by using the first-principles density functional theory and semiclassical Boltzmann transport theory, we demonstrate the significance of the atomic sites, valence electrons, spins, and stacking order to the electronic and thermal transport of the materials. We resolved discrepancies in theoretical and experimental investigations on β-Ga2O3's lattice thermal conductivity (κl), traditionally attributed to defects and temperature-dependent interatomic force constants, which provides a comprehensive understanding of modelling low-symmetry structures for accurate determination of κl. Next, we show that cationic sites can be effectively utilized to decouple and tune the electronic and thermal transport of the materials, particularly using spinel oxides, and highlight the fundamental understanding for suppressing bipolar electronic transport in narrow bandgap intermetallic semiconductors to achieve high thermoelectric performance. Finally, we show the crucial role of magnetic spin, which is also important in stabilizing the chromium trihalides, and the effect of stacking order in ReS2 on κl along all the conducting directions. Our study paves the way for a comprehensive understanding of heat and electronic transport mechanisms critically under different physical and chemical environments.