Structural studies of CuAlSe2, and CuAlS2 chalcopyrites at high pressures

The ternary chalcopyrite compounds CuAlSe2 and CuAlS2 were studied up to 14 .8 Cpa in a diamond anvil cell by energy dispersive X-ray diffraction (EDXR D). The powder X-ray diffraction data at high pressure show that CuAlSe2 un dergoes a pressure-induced structural phase transition around 12.5 GPa from the chalcopyrite structure to NaCl type structure. CuAlS2 exhibits structu ral stability up to 14.8 Cpa. The pressure-induced structural phase transit ion observed in the EDXRD experiments is consistent with the theoretical to tal energy calculations. The results are consistent with the conclusions of a recent high-pressure Raman study reported for these compounds. (C) 2000 Elsevier Science B.V. All rights reserved.