Reinterpretation of bond-valence model with bond-order formalism: an improved bond-valence based interatomic potential for PbTiO$_3$

摘要

We present a modified bond-valence model of PbTiO$_3$ based on the principlesof bond-valence and bond-valence vector conservation. The relationship betweenthe bond-valence model and the bond-order potential is derived analytically inthe framework of a tight-binding model. A new energy term, bond-valence vectorenergy, is introduced into the atomistic model and the potential parameters arere-optimized. The new model potential can be applied both to canonical ensemble($NVT$) and isobaric-isothermal ensemble ($NPT$) molecular dynamics (MD)simulations. This model reproduces the experimental phase transition in $NVT$MD simulations and also exhibits the experimental sequence oftemperature-driven and pressure-driven phase transitions in $NPT$ simulations.We expect that this improved bond-valence model can be applied to a broad rangeof inorganic materials.