| AVS 56th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Thursday Sessions |
| Session NS-ThA |
| Session: | Characterization & Imaging at the Nanoscale II |
| Presenter: | J. Yang, Paul Drude Institute for Solid State Electronics, Germany |
| Authors: | J. Yang, Paul Drude Institute for Solid State Electronics, Germany K. Kanisawa, NTT Corporation, Japan Ch. Nacci, Paul Drude Institute for Solid State Electronics, Germany S. Fölsch, Paul Drude Institute for Solid State Electronics, Germany |
| Correspondent: | Click to Email |
Atom manipulation by scanning tunneling microscopy (STM) at cryogenic temperatures has proven to be a powerful experimental tool to study the physics of assembled nanostructures at surfaces. Since its implementation in the early 1990s [1], STM-based manipulation has been applied mainly to atoms and molecules adsorbed on metal surfaces. Here we demonstrate the extension of this technique to III-V semiconductor materials and report the fully reversible repositioning of In adatoms on a InAs (111)A surface by vertical manipulation at 5 K, i.e., by transferring individual atoms from the surface to the STM tip and vice versa. This allows us to assemble compact structures with the In atoms added one by one and occupying nearest-neighbor vacancy sites of the (2x2)-reconstructed surface (separation of the vacancy sites a0√2=8.57 Å, a0: cubic InAs lattice constant). Combining this approach with scanning tunneling spectroscopy (STS), we studied the electronic properties of monatomic adatom chains representing a model case of a one-dimensional electron system. The STS data reveal substantial electronic coupling between the In chain atoms leading to the formation of an unoccupied quantum state delocalized along the chain. Regarding the substantial interatomic spacing of 8.57 Å present here it appears that substrate-mediated coupling is essential for the along-chain linking rather than direct interatomic coupling reported previously in metal-on-metal adatom chains [2,3]. Our results demonstrate that the combined approach of atom manipulation and local spectroscopy is applicable to explore atomic-scale quantum structures in a semiconductor-based system.
[1] J. A. Stroscio and D. M. Eigler, Science 254, 1319 (1991).
[2] N. Nilius, T. M. Wallis, and W. Ho, Science 297, 1853 (2002).
[3] S. Fölsch, P. Hyldgaard, R. Koch, and K. H. Ploog, Phys. Rev. Lett. 92, 56803 (2004).
Support by the Japanese Agency of Science &Technology (JST) and the German Research Foundation (DFG) is gratefully acknowledged.