Electronic Structure and Superconductivity in Binary and Ternary Hydrides Under Pressure

First principles calculations are employed to interrogate the electronic structure and bonding in two structures types that a priori crystal structure prediction methods have found for many compressed alkaline earth and rare earth metal binary hydrides: the I4/mmm symmetry tetrahydrides, and the Im-3m symmetry hexahydrides. We explore the relationship between their structure and electronic structure, as well as their propensity for superconductivity. Moreover, the XtalOpt evolutionary algorithm is used to predict the structures of novel stable and metastable ternary hydrides that could potentially be synthesized in high pressure experiments, and their superconducting critical temperatures are estimated.