THEORY OF OPTICAL REFLECTANCE ANISOTROPY OF THE NATURAL SI(110) SURFACE

We investigate theoretically the optical reflectance anisotropy of the natural Si(110) surface, including the surface intrinsic anisotropy a nd the surface local-field effect. We model a rough Si(110) surface, d etermining a number of defect structures by total-energy minimization. We show that a structure with missing Si atoms and partial H coverage gives a reflectance anisotropy in agreement with experiment, in contr ast to previous calculations for the ideally H-terminated Si(110) surf ace. We show that both the intrinsic anisotropy and the surface local- field effect are essential for such an agreement.