High pressure EXAFS on GaTe single crystal including polarization

The evolution of the local structure in GaTe under pressure is studied by X -ray absorption spectroscopy (XAS) at the Ga K-edge (10.368 keV) on oriente d single crystals. The use of the linear polarization of the synchrotron ra diation has allowed to determine the pressure evolution of both the Ga-Te a nd the in-plane Ga-Ga bond lengths, in spite of the small XAS signal of the latter. Our measurements show that both distances are much less compressib le than what could be inferred from the bulk compressibility, indicating a significant variation of Ga-Ga-Te and Te-Ga-Te angles under compression. In the high-pressure NaCl phase, no anisotropy of the XAS spectrum is detecte d and local and bulk compressibilities coincide.