The repositioning of native In adatoms on the polar III-V semiconductor surface InAs(111)A-(2 x 2) was achieved with atomic precision in a scanning tunnelling microscope at 5K. The repositioning was performed by vertical manipulation, i.e., a reversible transfer of an individual adatom between the surface and the scanning tunnelling microscope tip. Surface-to-tip transfer was achieved by a step-wise vibrational excitation of the adsorbate-surface bond via inelastic electron tunnelling assisted by the tip-induced electric field. In contrast, tip-to-surface back-transfer occurred upon tip-surface point contact formation governed by short-range adhesive forces between the surface and the In atom located at the tip apex. In addition, it was found that carrier transport through the point contact was not of a ballistic nature but was due to electron tunnelling. The vertical manipulation scheme used here permitted the assembly of nanostructures of diverse sizes and shapes with the In adatoms residing on vacancy sites of the (2 x 2)-reconstructed surface (nearest-neighbour vacancy spacing: 8.57Å).

Vertical Manipulation of Native Adatoms on the InAs(111)A Surface. J.Yang, C.Nacci, J.Martínez-Blanco, K.Kanisawa, S.Fölsch: Journal of Physics - Condensed Matter, 2012, 24[35], 354008