Atomically precise impurity identification and modification on the manganese doped GaAs(110) surface with scanning tunneling microscopy

Cross-sectional scanning tunneling microscopy (STM) measurements on mol. beam epitaxy grown Mn doped GaAs(110) at 5 and 77 K are presented. The enhanced mech. stability of the STM at low temp. allows a detailed study of the electronic contrast of Mn atoms in the GaAs(110) surface. According to reproducible and distinguishable contrast patterns of single Mn atoms, we present statistical evidence for a layer by layer identification of Mn atoms embedded in the first few monat. layers of the crystal. A comparison with a bulklike theor. approach reveals a semiquant. agreement with the measurements. Remaining differences between theory and expt. indicate the influence of the surface as an important factor to understand the contrast of impurities close to the surface. Furthermore, we report the injection of transition-metal atoms into the surface. Finally, reproducible complexes consisting of a surface Mn and an adsorbate atom are found and manipulated.