title: Polar-Soft-Mode-Driven Structural Phase Transition in SrTiO3.
abstract: The structural phase transition of SrTiO3 at 105 K, which has been believed to be independent of the ferroelectric soft mode [Phys. Rev. 177, 858 (1969)], is shown, on the contrary, to be driven by the same long-wavelength polar instability. Isotope replacement of 16O by 18O is predicted to cause an increase in the structural phase transition temperature by 3.8 K. In both isotopic cases, dynamical polarizability-induced ferroelastic-type cluster formation takes place above the structural phase transition, which is intrinsic and a consequence of electron-lattice driven mode-mode coupling. Distinct length and time scales are identified. The precursor domains are evidence that order-disorder effects coexist with displacive dynamics.
authors.affiliation: Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Bussmann-Holder
authors.forename: H
authors.initials: H
authors.lastname: Büttner
authors.forename: A R
authors.initials: AR
authors.lastname: Bishop