Ferroelectric-Monolayer Reconstruction of the SrTiO3(100) Surface

Computer simulations of the two (100) surfaces of cubic SrTi${\mathrm{O}}_3$ show that the top layer of the SrO-terminated surface reconstructs to a ferroelectric-monolayer phase while the Ti${\mathrm{O}}_2$-terminated surface remains bulklike. This behavior is shown to arise from a delicate crystal-environment sensitive competition between the long-range Coulomb and the short-range repulsive interactions.