Abstract
In the present study, we have made a theoretical approach based upon the first principles projector augmented wave (PAW) method to investigate the behavior of LaAlO3 and related perovskites under pressure. In addition to the conventional static total energy calculations, we have computed phonon states by using the direct method. The present calculations quantitatively well reproduce the experimentally observed phase transition pressure and the pressure dependence of phonon frequencies in LaAlO3, confirming the compound's exceptional behavior for the general rule. Further systematic calculations were made on a series of perovskites, providing a clue toward new general rule of displacive transitions.
