Structural and electronic transformations of GeSe2 glass under high pressures studied by X-ray absorption spectroscopy
Proceedings of the National Academy of Sciences of the United States of America, cilt.121, sa.14, 2024 (SCI-Expanded)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 121 Sayı: 14
- Basım Tarihi: 2024
- Doi Numarası: 10.1073/pnas.2318978121
- Dergi Adı: Proceedings of the National Academy of Sciences of the United States of America
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, Animal Behavior Abstracts, Aquatic Science & Fisheries Abstracts (ASFA), Artic & Antarctic Regions, BIOSIS, CAB Abstracts, Chemical Abstracts Core, EconLit, Food Science & Technology Abstracts, INSPEC, Linguistic Bibliography, MathSciNet, Pollution Abstracts, Psycinfo, Public Affairs Index, Veterinary Science Database, zbMATH, DIALNET, Nature Index
- Anahtar Kelimeler: chemical disorder, high pressure, polyamorphism, X-ray absorption spectroscopy
- Abdullah Gül Üniversitesi Adresli: Evet
Özet
Pressure-induced transformations in an archetypal chalcogenide glass (GeSe2) have been investigated up to 157 GPa by X-ray absorption spectroscopy (XAS) and molecular dynamics (MD) simulations. Ge and Se K-edge XAS data allowed simultaneous tracking of the correlated local structural and electronic changes at both Ge and Se sites. Thanks to the simultaneous analysis of extended X-ray absorption fine structure (EXAFS) signals of both edges, reliable quantitative information about the evolution of the first neighbor Ge-Se distribution could be obtained. It also allowed to account for contributions of the Ge-Ge and Se-Se bond distributions (chemical disorder). The low-density to high-density amorphous-amorphous transformation was found to occur within 10 to 30 GPa pressure range, but the conversion from tetrahedral to octahedral coordination of the Ge sites is completed above ∼ 80 GPa. No convincing evidence of another high-density amorphous state with coordination number larger than six was found within the investigated pressure range. The number of short Ge-Ge and Se-Se “wrong” bonds was found to increase upon pressurization. Experimental XAS results are confirmed by MD simulations, indicating the increase of chemical disorder under high pressure.