0000000000214997
AUTHOR
J. P. Itié
Single crystal EXAFS at high pressure
Abstract We present a new technique for structure characterization under high pressure conditions. The use of an undulator beam of the third-generation ESRF source of synchrotron radiation has enabled the first single crystal EXAFS experiments at high pressure using a diamond anvil cell as pressure generator. Taking advantage of the linear polarization of X-rays the technique becomes an orientation-selective probe of the local structure of materials. We describe the principle of the technique and some applications.
High-pressure x-ray-absorption study of GaSe
The III-VI layered semiconductor InSe has been studied by high-pressure single crystal x-ray absorption spectroscopy up to a maximum pressure of 14 GPa. The In-Se distance has been measured in both the low- pressure layered phase and the high-pressure NaCl phase. The bond compressibility in the layered phase is lower than the ``a'' crystallographic parameter compressibility, which implies an increase of the angle between the In-Se bond and the layer plane. Under plausible hypothesis, a description of the evolution of the whole structure with pressure is given. In particular, the intralayer distance is observed to increase with increasing pressure. A plausible precursor defect and a simple m…