MEMS/MatSci Seminar: Computational Discovery of New Materials Under Pressure
Wednesday, January 16, 2019 - 12:00pm
The pressure variable opens the door towards the synthesis of materials with unique properties, e.g. superconductivity, hydrogen storage media, high-energy density and superhard materials. Under pressure elements that would not normally combine may form stable compounds or they may mix in novel proportions. As a result, we cannot use our chemical intuition developed at 1 atm to predict phases that become stable when compressed. To enable our search for novel hydride phases that can be synthesized under pressure we have developed XtalOpt, an open-source evolutionary algorithm for crystal structure prediction. XtalOpt has been employed to find the most stable structures of hydrides with unique stoichiometries. Some of these are superconducting at high temperatures. Herein, we describe our predictions of the binary hydrides of scandium, phosphorus, calcium and iron. The electronic structure and bonding of the predicted phases is analysed by detailed first-principles calculations. We also describe an extension of XtalOpt towards the prediction of superhard materials.