MEMS/MatSci Seminar: Computational Discovery of New Materials Under Pressure

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.