Pressure-induced reversible phase transition on Mo2Ga2C
- Peking Univ. and School of Earth and Space Sciences, Beijing (China); China Academy of Engineering Physics, Mianyang (China)
- China Academy of Engineering Physics, Mianyang (China)
- Wuhan Univ. of Technology (China)
- Southwest Jiaotong Univ., Chengdu (China)
- China Univ. of Geosciences, Wuhan (China)
The newly carbide α-Mo2Ga2C with P63/mmc space group presents a unique top-packed Ga double layer structure. Pressure-induced phase transition of Mo2Ga2C has been investigated by in-situ high-pressure synchrotron radiation X-ray diffraction, Raman spectroscopy combined with diamond anvil cell technique, and first-principle calculations. Both experimental and theoretical results show that a first-order phase transition from P63/mmc to P3¯m1 occurs at ~22 GPa, where the high-pressure phase named β-Mo2Ga2C has a close-packed Ga double layer zig-zag structure. The isothermal pressure-volume relationship of Mo2Ga2C is described by the second-order Birch-Murnaghan equation of state, yielding K0 = 139(2) GPa, K0' = 4(fixed), and V0 = 144.5(1) Å3 for α-Mo2Ga2C; K0 = 187(3) GPa, K0' = 4(fixed), and V0 = 137.9(2) Å3 for β-Mo2Ga2C. The instability caused by the repulsive force between the Ga atoms in the top-packed double-layer under pressure mainly accounts for the phase transition. In conclusion, the newly discovered β-Mo2Ga2C reveals that the MAX-like M2A2X type ternary compounds with different compositions may form various structures with different space groups.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Natural Science Foundation of China (NSFC); Science and Technology Development Foundation of China Academy of Engineering Physics; National Science Foundation-Earth Sciences; Natural Sciences Foundation of China
- Grant/Contract Number:
- AC02-06CH11357; 91326102; 51532009; 51741208; 2013A0301012; EAR-1128799; FG02-94ER14466
- OSTI ID:
- 1468807
- Journal Information:
- Journal of Applied Physics, Vol. 124, Issue 8; ISSN 0021-8979
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- ENGLISH
Web of Science
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