Theoretical modeling of antiferrodistortive phase transition for SrTi O 3 ultrathin films

Combining group-theoretical analysis and first-principles density functional theory calculations, we confirm theoretically the antiferrodistortive phase transition in ultrathin SrTiO3 (001) TiO2-terminated films and compare it with a similar transition in the bulk. We demonstrate phonon softening at the M point of the surface Brillouin zone and analyze the change in the calculated electronic and phonon properties upon phase transition.