Enhanced dimerization of TiOCl under pressure: spin-Peierls to Peierls transition.
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.
Blanco-Canosa
S
S
Departamento de Química-Física, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Rivadulla
F
F
Piñeiro
A
A
Pardo
V
V
Baldomir
D
D
Khomskii
D I
DI
Abd-Elmeguid
M M
MM
López-Quintela
M A
MA
Rivas
J
J