Energetics of single- and double-layer steps on the Si(001) 2 x 1 surface calculated using the extended Brenner empirical potential

The extended Brenner potential has been shown to provide a good description of the (001) and (111) surfaces of silicon. In this paper, this empirical potential is employed to study the energetics of steps on the Si(001)2×1 surface. Particular attention has been paid to the dependence of the step energies on the width of the terraces and the number of substrate layers. Formation energies for both the single-layer SA and SB steps, and the double layer DA and DB steps, have been determined. All of the formation energies are found to be negative. Values of the step-step and surface stress interaction energy coefficients are also determined. The correlation of these results with experiment and previous theoretical calculations is discussed.