Structural phase transition of GaTe at high pressure

We have investigated structural stability and electronic properties of the layered semiconductor GaTe under hydrostatic pressure by X-ray powder diffraction and optical reflectivity measurements in a diamond anvil cell. The monoclinic low-pressure modification undergoes a first-order phase transition at 10(1) GPa into a high-pressure polymorph of the NaCl type structure. Thermal annealing at 475 K and 12 GPa for 12 h turned out to be essential for obtaining well-crystallized samples of the high-pressure phase. The reconstructive structural change is accompanied by a semiconductor-to-metal transition. The cubic modification is metastable with decreasing pressures down to 3 GPa and transforms to an amorphous phase at lower pressures