High-pressure Raman scattering study of defect chalcopyrite and defect stannite ZnGa2Se4

Abstract

Under the terms of the Creative Commons Attribution 3.0 Unported License.-- Trabajo presentado a la 49th European High Pressure Research Group Conference (EHPRG), celebrada en Mumbai (India) del 25 al 30 de septiembre de 2011.-- et al. ; High-pressure Raman scattering measurements have been carried out in ZnGa2Se4 for both tetragonal defect chalcopyrite and defect stannite structures. Experimental results have been compared with theoretical lattice dynamics ab initio calculations and confirm that both phases exhibit different Raman-active phonons with slightly different pressure dependence. A pressure-induced phase transition to a Raman-inactive phase occurs for both phases; however, the sample with defect chalcopyrite structure requires slightly higher pressures than the sample with defect stannite structure to fully transform into the Raman-inactive phase. On downstroke, the Raman-inactive phase transforms into a phase that could be attributed to a disordered zincblende structure for both original phases; however, the sample with original defect chalcopyrite structure compressed just above 20 GPa, where the transformation to the Raman-inactive phase is not completed, returns on downstroke mainly to its original structure but shows a new peak that does not correspond to the defect chalcopyrite phase. The pressure dependence of the Raman spectra with this new peak and those of the disordered zincblende phase is also reported and discussed. © 2013 AIP Publishing LLC. ; This study was supported by the Spanish government MEC under Grants No. MAT2010-21270-C04-01/03/04, by MALTA Consolider Ingenio 2010 project (CSD2007- 00045), and by the Vicerrectorado de Investigación y Desarrollo of the Universitat Politécnica de Valencia (UPV2011-0914 PAID-05-11 and UPV2011-0966 PAID-06-11). ; Peer Reviewed