Theoretical modifications of scandium oxychloride in extreme conditions as an example of rare earth compounds

Abstract

Theoretical modifications of ScOCl at extreme thermodynamic conditions have been identified and are studied as an example of rare earth element (RRE) compounds. Global optimizations with empirical potentials and local optimizations on the ab initio level were performed, leading to the identification of four new structure candidates on the energy landscape that are expected to be relevant under extreme conditions. The structural, as well as electronic properties of these polymorphs, have been investigated and compared with the modifications of the structure under standard conditions. Such theoretical explorations are very important since literature data regarding ScOCl is rather scarce, although ScOCl and the rare-earth elements (REEs) in general have a wide range of applications; for example, scandium is used in solid oxide fuel cells and could be used for potential future applications in photocatalysis or electronic devices, while oxyhalides of transition metals and REEs exhibit interesting magnetic and electronic properties.