324914 Application of Bond-Valence Theory for Developing Efficient Interatomic Potential for Oxides

Friday, November 8, 2013: 9:06 AM
Union Square 16 (Hilton)
Shi Liu, Ilya Grinberg and Andrew M. Rappe, Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA

First-principles density functional theory (DFT) calculations have played an important role in enhancing microscopic understanding of intrinsic effects (e.g., compositions and structures) on material properties of oxides.[1-2] For elucidating the changes (dynamics) in material behaviors with extrinsic effects, such as temperature, strain, and electric field, large system sizes and long simulations are necessary. Conventional first-principles methods for large systems and long-time simulations are limited due to their intense computational costs. There is therefore still a strong need to develop accurate and efficient atomistic potential that could reproduce the full dynamical behaviors of metal oxides. [3-9] The development of general atomistic potentials for oxides has proven difficult due to the complex nature of various metal-oxygen bonds.[10]

In this work, we developed a bond-valence model based on the principles of bond-valence and bond-valence vector conservation. [11-12] The relationship between the bond-valence model and the bond-order potential is derived analytically in the framework of a tight-binding model, demonstrating that our model is formally equivalent to the bond-order potential, but is dramatically more efficient computationally. A new energy term, bond-valence vector energy, is introduced into the atomistic model. The force fields for PbTiO3 and BiFeO3 are parameterized respectively. [13] The new model potential can be applied to both canonical ensemble (NVT) and isobaric-isothermal ensemble (NPT) molecular dynamics (MD) simulations. Our model potential can reproduce the experimental phase transition in NVT MD simulations and also exhibit the experimental sequence of temperature-driven and pressure-driven phase transitions in NPT simulations. We expect that our bond-valence model can be applied to a broad range of inorganic materials.

References

[1] W. Zhong, R.D. King-Smith, and D. Vanderbilt, Phys Rev Lett 72, 3618 (1994).

[2] I. Grinberg and A.M. Rappe, Phys Rev B 70, 220101 (2004).

[3] M. Sepliarsky and R.E. Cohen, AIP Conf. Proc. 626, 36 (2002).

[4] T. Shimada, K. Wakahara, Y. Umeno, and T. Kitamura, J. Phys.: Condens. Matter, 20, 325225 (2008).

[5] M. Sepliarsky, A. Asthagiri, S.R. Phillpot, M.G. Stachiotti, and R.L. Migoni, Curr. Opin. Solid State Mater. Sci. 9, 107 (2005).

[6] I. Grinberg, V.R. Cooper and A.M. Rappe, Nature 419, 909 (2002).

[7] W. Zhong, D. Vanderbilt, and K.M. Rabe, Phys. Rev. B 52, 6301 (1995).

[8]  U.V. Waghmare and K.M. Rabe, Phys. Rev. B 55, 6161 (1997).

[9]  Y.-H. Shin, V.R. Cooper, I. Grinberg and A.M. Rappe, Phys. Rev. B 71, 054104 (2005).

[10] S.R. Phillpot, S.B. Sinnott, and A. Asthagiri, Annu. Rev. Mater. Res. 37, 239 (2007).

[11] I.D. Brown, Chem. Rev. 109, 6858 (2009).

[12] M.A. Harvey, S. Baggio, and R. Baggio, Acta Crystallogr. B62, 1038, (2006).

[13] S. Liu, I. Grinberg, and A. M. Rappe,  J. Phys. Cond. Matt. 25, 102202 (2013)


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