Abstract
By pressure-dependent infrared microspectroscopy, we observe the filling of the Mott–Hubbard gap in TiOCl and TiOBr above a critical pressure P c. Concomitant with the gap filling, a structural phase transition occurs at P c. According to our pressure-dependent powder X-ray diffraction data, a mixture of the ambient-pressure orthorhombic Pmmn phase and a dimerized, monoclinic P21/m phase exists above P c.
Acknowledgements
We acknowledge the ANKA Angströmquelle Karlsruhe and the European Synchrotron Radiation Facility for the provision of beamtime. Financial support by the DFG (Emmy Noether-program, SFB 484, DFG-CL124/6-1) is acknowledged.