Using a highly accurate tight-binding total-energy approach applied to large super-cells, the local bonding behavior and the domain size relationship were studied for vacancy lines on Si(001) over a wide range of surface dimer vacancy density, θ. For vacancy lines perpendicular to surface dimer rows, strong local bonding interactions exist at the vacancy line edges and between neighboring vacancy lines. Delicate balance between strain release and re-bonding led to sensitive dependence of local bonding configurations on θ. On the other hand, for vacancy lines parallel to surface dimer rows all excessive dangling bonds re-bonded, leading to much weaker interactions between vacancy lines and a distribution pattern drastically different from that of perpendicular vacancy lines. Further examination of the vacancy line domain size relation revealed an effective long-range interaction decaying as 1/r2 for perpendicular vacancy lines, but not for parallel vacancy lines.

Local Bonding Behavior and Domain Size Relation for Vacancy Lines on Si(001). E.Kim, C.Chen: Physical Review B, 2002, 66[20], 205418 (5pp)