X-ray diffraction study on pressure-induced phase transformations and the equation of state of ZnGa_2Te_4

摘要

We report on high-pressure x-ray diffraction measurements up to 19.8 GPa in zinc digallium telluride (ZnGa_2Te_4) at room temperature. An irreversible structural phase transition takes place at pressures above 12.1 GPa and upon decompression a third polymorph of ZnGa_2Te_4 was recovered as a metastable phase at pressures below 2.9 GPa. Rietveld refinements were carried out for the three detected polymorphs, being their possible crystal structures reported. The axial compressibilities for the low-pressure phase of ZnGa_2Te_4 have been determined as well as the equation of state of the low- and high-pressure phases. The reported results are compared with those available in the literature for related compounds. Pressure-induced coordination changes and transition mechanisms are also discussed.