Crystal structures and electronic properties of solid fluorine under high pressure
As the previously proposed structures of C2/m and C2/c possess similar enthalpies and x-ray diffraction patterns, the space group of fluorine at ambient pressure is in controversy. We successfully obtain its thermodynamically stable lowpressure phase, which shares the same structure as the earlier k...
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| Published in | Chinese physics B Vol. 26; no. 7; pp. 276 - 282 |
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| Main Author | |
| Format | Journal Article |
| Language | English |
| Published |
01.06.2017
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| Subjects | |
| Online Access | Get full text |
| ISSN | 1674-1056 2058-3834 |
| DOI | 10.1088/1674-1056/26/7/076103 |
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| Summary: | As the previously proposed structures of C2/m and C2/c possess similar enthalpies and x-ray diffraction patterns, the space group of fluorine at ambient pressure is in controversy. We successfully obtain its thermodynamically stable lowpressure phase, which shares the same structure as the earlier known C2/c. Further investigations on phonon spectra reveal the instability of the C2/m structure with imaginary frequency in the Brillouin zone and confirm the dynamically stable property of the C2/c structure at the same time. Compressing fluorine up to 8 GPa, the C2/c phase is found to undergo a phase transition to a new structure with a space group of Cmca. Electronic energy band structures indicate the insulating feature of C2/c and Cmca with no bands across the Fermi level. The infrared（IR） and Raman spectra of C2/c and Cmca at selected pressures are calculated to provide useful information to future experiments. |
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| Bibliography: | fluorine; structure; insulating feature Qianqian Lv,Xilian Jin,Tian Cui,Quan Zhuang,Ying Li,Youchun Wang,Kuo Bao,Xing Meng（ State Key Laboratory of Superhard Materials, College of Physics, Jilin Univer, sity, Changchun 130012, China） As the previously proposed structures of C2/m and C2/c possess similar enthalpies and x-ray diffraction patterns, the space group of fluorine at ambient pressure is in controversy. We successfully obtain its thermodynamically stable lowpressure phase, which shares the same structure as the earlier known C2/c. Further investigations on phonon spectra reveal the instability of the C2/m structure with imaginary frequency in the Brillouin zone and confirm the dynamically stable property of the C2/c structure at the same time. Compressing fluorine up to 8 GPa, the C2/c phase is found to undergo a phase transition to a new structure with a space group of Cmca. Electronic energy band structures indicate the insulating feature of C2/c and Cmca with no bands across the Fermi level. The infrared（IR） and Raman spectra of C2/c and Cmca at selected pressures are calculated to provide useful information to future experiments. 11-5639/O4 |
| ISSN: | 1674-1056 2058-3834 |
| DOI: | 10.1088/1674-1056/26/7/076103 |