High-pressure x-ray diffraction study on the structure and phase transitions of the defect-stannite ZnGa[subscript 2]Se[subscript 4] and defect-chalcopyrite CdGa[subscript 2]S[subscript 4]
- UNLV
X-ray diffraction measurements on the sphalerite-derivatives ZnGa{sub 2}Se{sub 4} and CdGa{sub 2}S{sub 4} have been performed upon compression up to 23 GPa in a diamond-anvil cell. ZnGa{sub 2}Se{sub 4} exhibits a defect tetragonal stannite-type structure (I{bar 4}2m) up to 15.5 GPa and in the range from 15.5 to 18.5 GPa the low-pressure phase coexists with a high-pressure phase, which remains stable up to 23 GPa. In CdGa{sub 2}S{sub 4}, we find that the defect tetragonal chalcopyrite-type structure (I{bar 4}) is stable up to 17 GPa. Beyond this pressure a pressure-induced phase transition takes place. In both materials, the high-pressure phase has been characterized as a defect-cubic NaCl-type structure (Fm{bar 3}m). The occurrence of the pressure-induced phase transitions is apparently related with an increase in the cation disorder on the semiconductors investigated. In addition, the results allow the evaluation of the axial compressibility and the determination of the equation of state for each compound. The obtained results are compared to those previously reported for isomorphic digallium sellenides. Finally, a systematic study of the pressure-induced phase transition in 23 different sphalerite-related ABX{sub 2} and AB{sub 2}X{sub 4} compounds indicates that the transition pressure increases as the ratio of the cationic radii and anionic radii of the compounds increases.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1006851
- Journal Information:
- J. Appl. Phys., Vol. 104, Issue 2008; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- ENGLISH
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