Molecular Dynamics Modeling of Nanoscale CaF₂/BaF₂ Heterolayer Structures

Abstract

We present a transferable technique for the preparation of atomistic models mimicking ion conductor heterolayers grown by molecular beam epitaxy. On this basis, CaF 2 /BaF 2 sandwich structures involving (100), (110), and (111) interfaces were explored. Our molecular dynamics simulations reveal a close interplay of interface-driven lattice deformation and resulting dislocations with the fluoride ion redistribution and local conductivity. From this, an interfacial core region of about 1 nm thickness can be assessed, accompanied by a space charge zone in BaF 2 that is, however, three times thicker. Significant conductivity effects owing to charge carrier redistribution are found, which are closely related to the experimental results on this system.