title: Enhanced dimerization of TiOCl under pressure: spin-Peierls to Peierls transition.
abstract: We report x-ray diffraction and magnetization measurements under pressure combined with ab initio calculations to show that high-pressure TiOCl corresponds to an enhanced Ti3+-Ti3+ dimerized phase existing already at room temperature. Our results demonstrate the formation of a metal-metal bond between Ti3+ ions along the b axis of TiOCl, accompanied by a strong reduction of the electronic gap. The evolution of the dimerization with pressure suggests a crossover from the spin-Peierls to a conventional Peierls situation at high pressures.
authors.affiliation: Departamento de Química-Física, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Blanco-Canosa
authors.forename: F
authors.initials: F
authors.lastname: Rivadulla
authors.forename: A
authors.initials: A
authors.lastname: Piñeiro
authors.forename: V
authors.initials: V
authors.lastname: Pardo
authors.forename: D
authors.initials: D
authors.lastname: Baldomir
authors.forename: D I
authors.initials: DI
authors.lastname: Khomskii
authors.forename: M M
authors.initials: MM
authors.lastname: Abd-Elmeguid
authors.forename: M A
authors.initials: MA
authors.lastname: López-Quintela
authors.forename: J
authors.initials: J
authors.lastname: Rivas