Development of a bond-valence based interatomic potential for BiFeO3 for accurate molecular dynamics simulations

We present an atomistic potential for BiFeO3 based on the principles of bond-valence (BV) and bond-valence vector (BVV) conservation. The validity of this model potential is tested for both canonical ensemble (NVT) and isobaric-isothermal ensemble (NPT) molecular dynamics (MD) simulations. The model reproduces the ferroelectric-to-paraelectric phase transition in both NVT and NPT MD simulations and the temperature dependence of the local structure in BiFeO3. The calculated domain wall energies for 71 degrees, 109 degrees and 180 degrees walls agree well with density functional theory results. The success of our simple model potential for BiFeO3 indicates that BV and BVV conservation provides a firm basis for the development of accurate atomistic potentials for complex oxides.