Blanco-Canosa S, Rivadulla F, Piñeiro A, Pardo V, Baldomir D, Khomskii D I, Abd-Elmeguid M M, López-Quintela M A, Rivas J
Departamento de Química-Física, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Phys Rev Lett. 2009 Feb 6;102(5):056406. doi: 10.1103/PhysRevLett.102.056406.
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.
我们报告了在压力下进行的X射线衍射和磁化测量，并结合从头算计算，结果表明高压TiOCl对应于一种在室温下就已存在的增强型Ti3+-Ti3+二聚体相。我们的结果表明，沿着TiOCl的b轴，Ti3+离子之间形成了金属-金属键，同时电子能隙大幅减小。二聚化随压力的演变表明，在高压下从自旋佩尔斯状态转变为传统的佩尔斯状态。
