Atom Manipulation and Force Spectroscopy on Cu ( 110 )-O Surface with Low Temperature Atomic Force Microscopy

We introduce a novel atom-by-atom creation and evaluation system based on the atomic force microscopy at room temperature (RT). It can identify chemical species of individual atoms and then manipulate selected atom species to the designed site one-by-one to create composite nanostructures consisted of many atom species at RT Noncontact atomic force microscopy (NC-AFM) [1,2] based on the frequency modulation (FM) detection method can now not only image individual atoms but also construct atom letters using the atom manipulation method. Therefore, the NC-AFM is the next generation atom tool following the well-known scanning tunneling microscopy (STM). The NCAFM, however, has the advantages that it can image even insulating surfaces with atomic resolution and also measure the atomic force itself between the tip-apex outermost atom and the sample surface atom. Noting these advantages, we have been developing a novel atom-by-atom creation and evaluation system based on the NC-AFM. It can identify chemical species of individual atoms [3] and then manipulate selected atom species to the designed site one-by-one to create composite nanostructures consisted of many atom species at room temperature (RT) [4] as shown in Fig.1. In this review talk, we will introduce our results toward atom-by-atom creation and evaluation of composite nanostructures based on the NC-AFM at RT. To identify chemical species, we developed the sitespecific force spectroscopy at RT by compensating the thermal drift using the atom tracking. Thus we obtained the precise site-specific frequency shift curves and then converted them into the short-range force curves of selected Sn and Si atoms, respectively. Then using the atom-by-atom force spectroscopy at RT, we succeeded in chemical identification of intermixed three atom species in Pb/Sn/ Si(111)-(r3xr3) surface [3]. Besides we found the lateral atom interchange phenomenon at RT, which enables us to exchange embedded heterogeneous atoms [4]. By combining this phenomenon with the vector scan, we constructed the embedded atom letters “Sn” consisted of substituted Sn atoms embedded in Ge atoms at RT [4] as shown in Fig.2. In addition to the above results, today we will introduce our recent results on force mapping, another kind of the embedded atom letters “Si” created by the advanced single atom pen method [5] as shown in Fig.3, and the simultaneous evaluation of the force and current at the atomic scale using the combined AFM/STM. *Corresponding author: smorita@eei.eng.osaka-u.ac. jp [1] S. Morita, R. Wiesendanger, and E. Meyer (eds.); “Noncontact Atomic Force Microscopy”, Springer, NanoScience and Technology, 2002. [2] S. Morita, F. J. Giessibl, and R. Wiesendanger (eds.); “Noncontact Atomic Force Microscopy”, Vol.2, Springer, NanoScience and Technology, 2009. [3] Y. Sugimoto, P. Pou, M. Abe, P. Jelinek, R. Pérez, S. Morita, and O. Custance, Nature, 446, 64 (2007). [4] Y. Sugimoto, M. Abe, S. Hirayama, N. Oyabu, O. Custance, and S. Morita, Nature Materials, 4, 156 (2005). [5] Y. Sugimoto, P. Pou, O. Custance, P. Jelinek, M. Abe, R. Pérez and S. Morita, Science, 322, 413 (2008). Figure 2: Embedded atom letters “Sn” constructed by lateral atom interchange manipulation at RT Figure1: Schematic models and experimental results on (a) atom imaging, (b) chemical identification of intermixed individual atoms, (c) embedded atom letters constructed by lateral atom interchange manipulation and (d) embedded atom letters constructed by vertical atom interchange manipulation using the interchangeable single atom pen based on the atomic force microscopy at room temperature Figure 3: Embedded atom letters “Si” constructed by vertical atom interchange manipulation using the interchangeable single atom pen based on the atomic force microscopy at room temperature at RT Plenary Talk