We develop a first-principles scheme to study ferroelectric phase transitions for perovskite compounds. We obtain an effective Hamiltonian which is fully specified by first-principles ultra-soft pseudopotential calculations. This approach is applied to BaTiO3, and the resulting Hamiltonian is studied using Monte Carlo simulations. The calculated phase sequence, transition temperatures, latent heats, and spontaneous polarizations are all in good agreement with experiment. The order-disorder vs.\ displacive character of the transitions and the roles played by different interactions are discussed.
@article{arxiv.cond-mat/9406049,
title = {Phase transitions in BaTiO$_3$ from first principles},
author = {W. Zhong and David Vanderbilt and K. M. Rabe},
journal= {arXiv preprint arXiv:cond-mat/9406049},
year = {2009}
}