Ab-initio studies of pressure induced phase transitions in BaO

Date

2002-01-01

Author

Uludogan, M
Cagin, T
Strachan, A
Goddard, WA

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We use ab-initio Quantum Mechanics to study the zero temperature phase diagram of BaO. We calculate zero temperature Equations of State of different crystalline phases [B1 (NaCl), B8(NiAs), B2(CsCl), and distorted B2] using Density Functional Theory (DFT) with the generalized gradient approximation (GGA). We find the B1 structure to be the thermodynamically stable one at zero pressure; followed by three pressure induced phase transitions. We find that at P=11.3 GPa BaO transforms from B1 to B8; at P=21.5 GPa from B8 to distorted B2. The distorted B2 phase continuously approaches the B2 structure, the phase transformation occurs at P=62 GPa. We also study the band structure of BaO in its high pressure (B2) phase. For P=60.5 GPa, we find a band gap of 3.5 eV in agreement with experimetal value. We find metallization at P=230.6 GPa.

Subject Keywords

Alkaline-earth oxides, Equation of state, Metallization, Phase transformation

URI

https://hdl.handle.net/11511/67488

Journal

JOURNAL OF COMPUTER-AIDED MATERIALS DESIGN

Collections

Department of Physics, Article

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Citation Formats

M. Uludogan, T. Cagin, A. Strachan, and W. Goddard, “Ab-initio studies of pressure induced phase transitions in BaO,” JOURNAL OF COMPUTER-AIDED MATERIALS DESIGN, pp. 193–202, 2002, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/67488.