Structures and electronic states of the InSb{1 1 1}A,B-(2×2) surfaces

Scanning tunneling microscopy (STM) has been used to study surface structures and electronic states of the InSb{1 1 1}A,B-(2×2) surfaces. High-resolution STM images taken at various sample bias voltages for these two surfaces teach us the origin of the electronic states eigen to the In-vacancy buckling and the Sb-trimer structure. The former is characterized by a complete charge transfer from the In-atom of the outermost surface to the Sb atom of the second layer, whereas in the latter case an incomplete charge transfer is dominant. The incomplete charge transfer from the Sb-trimer to the rest-Sb atom is caused by a large deformation of the orbital configuration inherent to the rest-Sb atom.