Insights on the stability of cuprous chloride under high pressure: An equilibrium ab initio atomistic thermodynamics study

Abstract

Density functional theory, in conjunction with ab initio atomistic thermodynamics, were used to investigate the stability of the low index cuprous chloride surfaces, and predict the morphology of CuCl nanocrystals under high pressures of chlorine. The rocksalt orientation of the lattice was adopted to resemble a CuCl crystal under high pressure. Under Cl-lean conditions, the defective CuCl(100)+Cl structure was found to be the most stable configuration among all surfaces investigated. Under Cl-rich conditions, a flawless, CuCl(111) surface with Cl-termination becomes the most stable configuration. It was shown that in a diluted chlorine environment, the CuCl in zinc blende structures are more stable than the CuCl in rocksalt configurations, while under a chlorine rich environment, the CuCl in rocksalt structures are more stable than the CuCl in zinc blende configurations. At low pressure of chlorine, it was found that the (100) facets are the most dominant to the Wulff construction, giving the crystal a coffin shape. As the pressure of chlorine increases, however, the involvement of the (111) facet increases giving the crystal a semi dodeca-hedron shape. At high pressure of chlorine, the major contributors to the Wulff construction were found to be the (111) facets, resulting in the formation of dodeca-hedron nanocrystals.