Materials Theory Group
Seminar: Some perspectives on thermal and thermodynamic modeling of materials
Abstract: Ab initio materials modeling is now an important ingredient in understanding and predicting the properties of new compounds. Two important areas of application of predictive materials modeling are thermal transport, and thermodynamic stability. I will illustrate these areas through two recent works of our group. Firstly, I will present calculations of the effect of various dopants on the thermal conductivity of cubic boron arsenide, a promising novel compound for next generation power electronics. Amongst other group IV dopants, our calculations highlight Ge as being able to reach high doping levels while keeping a high thermal conductivity. The calculations also predict a noticeable signature of the onset of compensation, on the thermal conductivity . Secondly, I will discuss the prediction of phase diagrams of complex mixed transition-metal oxides for thermochemical energy storage. (CoxMn1−x)3O4 is a candidate to replace molten salts for energy storage in concentrated solar power generation. Modelling this system is challenging due to the many different entropy sources affecting the free energy, and with the prohibitive amount of configurations needed in the configurational space. I will present our calculation of the experimental hausmannite-spinel solubility gap for this compound, using machine learning to extend an ab initio dataset of hundreds of structures, and including many different entropic contributions to the free energy [2,3]. I will also briefly discuss some of our current efforts to investigate the reaction kinetics of these materials, and their potential impact on sustainable energy production.
 Mauro Fava, Nakib H. Protik, Chunhua Li, Navaneetha Krishnan Ravichandran, J. Carrete, A. van Roekeghem, G. K. H. Madsen, N. Mingo and D. Broido. How dopants limit the ultrahigh thermal conductivity of BAs: a first principles study. NPJ comp. materials, accepted (2021).
 S. K. Wallace, A. van Roekeghem, A. S. Bochkarev, J. Carrasco, A. Shapeev, and N. Mingo, “Modeling the high-temperature phase coexistence region of mixed transition metal oxides from ab initio calculations,” Phys. Rev. Research, 3, 013139 (2021).
 S. K. Wallace, A. S. Bochkarev, A. van Roekeghem, J. Carrasco, A. Shapeev, and N. Mingo, “Free energy of (CoxMn1-x)3O4 mixed phases from machine-learning-enhanced ab initio calculations,” Phys. Rev. Materials, 5, 035402 (2021).
About the speaker: Natalio Mingo founded the materials theory group at LITEN, CEA-Grenoble in 2007. Prior to this appointment he was a staff scientist at NASA Ames Research Center in California (2000-2006). He has been the principal investigator on numerous research projects funded by the US National Science Foundation, NASA, and the EU, among others. Dr. Mingo has authored numerous publications; he is also the originator of the shengBTE and almaBTE software projects.
Host: Mona Zebarjadi, assistant professor of electrical and computer engineering and materials science and engineering