Computational and experimental imaging of Mn defects on GaAs (110) cross-sectional surfaces

We present a combined experimental and computational study of the (110) cross-sectional surface of Mn delta-doped GaAs samples. We focus our study on three different selected Mn defect configurations not previously studied in detail, namely surface interstitial Mn, isolated and in pairs, and substitutional Mn atoms on cationic sites (Mn-Ga) in the first subsurface layer. The sensitivity of the scanning tunneling microscopy (STM) images to the specific local environment allows us to distinguish between Mn interstitials with nearest-neighbor As atoms (Int(As)) rather than Ga atoms (Int(Ga)), and to identify the fingerprint of peculiar satellite features around subsurface substitutional Mn. The simulated STM maps for Int(As), both isolated and in pairs, and Mn-Ga in the first subsurface layer are consistent with some experimental images hitherto not fully characterized.