Mott-Hubbard gap closure and structural phase transition in the oxyhalides TiOBr and TiOCl under pressure

被引：21

作者：

Kuntscher, C. A. ^{[1
]}

Pashkin, A. ^{[1
]}

Hoffmann, H. ^{[1
]}

Frank, S. ^{[1
]}

Klemm, M. ^{[1
]}

Horn, S. ^{[1
]}

Schoenleber, A. ^{[2
]}

van Smaalen, S. ^{[2
]}

Hanfland, M. ^{[3
]}

Glawion, S. ^{[4
]}

Sing, M. ^{[4
]}

Claessen, R. ^{[4
]}

机构：

[1] Univ Augsburg, D-86135 Augsburg, Germany

[2] Univ Bayreuth, Crystallog Lab, D-95440 Bayreuth, Germany

[3] European Synchrotron Radiat Facil, F-38043 Grenoble, France

[4] Univ Wurzburg, D-97074 Wurzburg, Germany

来源：

PHYSICAL REVIEW B | 2008年 / 78卷 / 03期

关键词：

D O I：

10.1103/PhysRevB.78.035106

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Pressure-dependent transmittance and reflectance spectra of TiOBr and TiOCl single crystals at room temperature suggest the closure of the Mott-Hubbard gap, i.e., the gap is filled with additional electronic states extending down to the far-infrared range. According to pressure-dependent x-ray powder-diffraction data, the gap closure coincides with a structural phase transition. The transition in TiOBr occurs at slightly lower pressure (p=14 GPa) compared to TiOCl (p=16 GPa) under hydrostatic conditions, which is discussed in terms of the chemical pressure effect. The results of pressure-dependent transmittance measurements on TiOBr at low temperatures reveal similar effects at 23 K, where the compound is in the spin-Peierls phase at ambient pressure.

引用

页数：10

共 38 条

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