Ab-initio studies of pressure induced phase transitions in BaO
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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.
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- 1.Jog, K.N., Singh, R.K. and Sanyal, S.P., Phys. Rev. B31 (1985) 6047.Google Scholar
- 3.Mehl, M.H., Hemley, R.J., Boyer, L.L., Phys. Rev. B33 (1986) 8685.Google Scholar
- 4.Jog, K.N., Sanyal, S.P. and Singh, R.K., Phys. Rev. B35 (1987) 5235.Google Scholar
- 5.Mehl, M.J., Cohen, R.E. and Krakuer, H., J. Geophys. Res. 93 (1988) 8009.; J. Geophys. Res. 94 (1989) 1977.Google Scholar
- 6.Kalpana, G., Palanivel, B. and Rajagopalan, R., Phys. Rev. B52 (1995) 4.Google Scholar
- 9.Strachan, A., Çağin, T. and Goddard III, W.A., Phys. Rev. B60 (1999) 15084.Google Scholar
- 11.Weir, S.T., Vohra, Y.K. and Ruoff, A.L., Phys. Rev. B33 (1986) 4221.Google Scholar
- 15.Perdew, J.P. and Wang, U., Phys. Rev. B46 (1992) 6671.Google Scholar
- 16.Vanderbilt, D., Phys. Rev. B41 (1990) 7892.Google Scholar
- 17.Rose, J.H., Smith, J.R., Guinea, F. and Ferrante, J., Phys. Rev. B29 (1984) 2963.Google Scholar
- 22.Bukowinski, M.S.T. and Hauser, J., Geophys. Res. Lett. 7 (1980) 689.Google Scholar