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Ab-initio studies of pressure induced phase transitions in BaO

  • Mustafa Uludoğan
  • Tahir ÇağIn
  • Alejandro Strachan
  • William A. GoddardIII
Article

Abstract

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.

Alkaline-earth oxides Equation of state Metallization Phase transformation 

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Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  • Mustafa Uludoğan
    • 1
  • Tahir ÇağIn
    • 1
  • Alejandro Strachan
    • 1
  • William A. GoddardIII
    • 1
  1. 1.Materials and Process Simulation Center, Beckman Institute (139-74)California Institute of TechnologyU.S.A

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