Metallization and superconductivity of BeH{sub 2} under high pressure
- State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China)
- Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada)
- Computational Astrophysics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)
Pressure-induced metallization and potential superconductivity of BeH{sub 2} has been a topic of interest. In the present study, we extensively explored the crystal structures of BeH{sub 2} in a wide pressure range of 0–300 GPa using an unbiased structure searching method coupled with first-principles density functional calculations. A series of pressure-induced structural transformations are predicted for BeH{sub 2}, as Ibam (α phase) → P-3m1 (phase II) → R-3m (phase III) → Cmcm (phase IV). Calculated pressures of phase transition are 25, 140, and 202 GPa, respectively. The phase II is isostructural to the well-known 1T structure of transition metal dichalcogenides, which is composed of covalent bonded BeH{sub 2} slabs stacked along the perpendicular direction by van der Waals forces. The phase III is constructed by the same BeH{sub 2} slabs, but differs from the phase II in the stacking sequence. The α phase, phase II, and phase III all have insulating electronic states while their band gaps decrease as pressure increases. We predicted that BeH{sub 2} reaches a metallic state by a III → IV phase transition, instead of a direct band gap closure in phase III. The phase IV has a three-dimensional extended Be-H network formed by edge-sharing BeH{sub 8} polyhedrons with delocalized electrons. Electron-phonon coupling calculations implemented using linear response theory on the metallic BeH{sub 2} predict a large electron-phonon coupling parameter of 0.63, leading to an estimation of superconducting transition temperature (T{sub c}) of ∼38 K at 250 GPa.
- OSTI ID:
- 22253383
- Journal Information:
- Journal of Chemical Physics, Vol. 140, Issue 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Theoretical studies of hard materials, novel conductors, and high-pressure phases of solids
Structural, Vibrational, and Electronic Properties of 1D-TlInTe2 under High Pressure: A Combined Experimental and Theoretical Study