We present an improved potential for silicon based on the bond order formalism that includes effects from the covalent screening of atoms by neighboring atoms. The potential expression was motivated by the success of the empirical bond order potentials of Tersoff (1) and Brenner (2) and the subsequent elucidation of their theoretical foundations in the form of analytical bond order

potential of Pettifor (3, 4).

The screening expression also makes it possible to extend the range of the potential to account for long range interactions that are essential for predicting some useful properties of silicon. The potential was fitted to experimental and DFT equation of state parameters for ten silicon phases. The result gave an overall improvement in equilibrium bond energies, volume and bulk modulus

for most phases of silicon compared to some existing silicon potentials like Tersoff.

A detailed comparison of this potential with some existing silicon potentials in terms of accuracy and predictive capability will be presented.

References

(1) J. Tersoff, Phys. Rev. B, 37, 6991 (1988).

(2) D. W. Brenner et al, J . Phys. Condens. Matter. 14,

783 (2002).

(3) D. G. Petiffor, et al, Mat. Sci. and Eng. A365, 2 (2004).

(4) D. Nguyen-Mahn et al, Bull. Mater. Sci. 26, 43 (2003).