Tungsten tip of a low-temperature scanning tunneling microscope is brought into contact with individual Co atoms adsorbed on Cu(100). Using this method is preferable compared to break junctions for the reason that it enables the setup of a more controllable contact. At G~G0 a smooth transition from the tunneling regime to contact occurs. Concomitantly, the characteristic dI/dV Fano line shape is broadening resulting in an increased Kondo temperature in contact. This enables to modify the many-body Kondo ground state by varying the distance of the tunneling tip from the adatom in a controllable way. Calculations indicate that the proximity of the tip shifts the d band of the Co adatom which affects the Kondo temperature.
References:
1. N. Néel, J. Kröger, L. Limot, K. Palotás, W. A. Hofer, and R. Berndt, Physical Review Letters 98, 016801 (2007).
2. R. Z. Huang, V. S. Stepanyuk, A. L. Klavsyuk, W. Hergert, P. Bruno, and J. Kirschner, Physical Review B 73, 153404 (2006).
3. O. Ujsághy, J. Kroha, L. Szunyogh, and A. Zawadowski, Physical Review Letters 85, 2557 (2000). |