Cross-sectional STM of Mn-doped GaAs: theory and experiment

We report first-principles calculations of the energetics and simulated scanning tunneling microscopy (STM) images for Mn dopants near the GaAs (110) surface, and compare the results with cross-sectional STM images. The Mn configurations considered here include substitutionals, interstitials, and complexes of substitutionals and interstitials in the first three layers near the surface. Based on detailed comparisons of the simulated and experimental images, we identify three types of Mn configurations imaged at the surface: (1) single Mn substitutionals, (2) pairs of Mn substitutionals, and (3) complexes of Mn substitutionals and interstitials.