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O: Fachverband Oberflächenphysik
O 104: Poster Session VIII: Scanning probe techniques: Method development III
O 104.2: Poster
Thursday, March 4, 2021, 13:30–15:30, P
The Quantum Corral - Bond to an artificial atom — •Fabian Stilp1, Andreas Bereczuk2, Julian Berwanger1, Nadine Mundigl1, Klaus Richter2, and Franz J. Giessibl1 — 1Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany — 2Institute of Theoretical Physics, University of Regensburg, 93053 Regensburg, Germany
In 1993 Crommie, Lutz and Eigler first created a quantum corral, an adatom structure that confines surface state electrons on metal surfaces, and investigated discrete energy states inside the corral using scanning tunneling microscopy (STM) [1]. We revisit the same corral, a ring of 48 iron atoms on a Cu(111) surface with a diameter of 14.26 nm, with atomic force microscopy (AFM) to investigate the bonding of this artificial atom to the front atom of the AFM-tip. The measured forces on the order of 100 femtonewtons reveal a covalent attraction to metal tips and Pauli repulsion to CO terminated tips. This is familiar to the interactions of these tips with natural atoms, so one would also expect repulsive interaction for closer distances between the front atom of the metal tip and the quantum corral. It is not possible to measure this repulsive force, because the tip is not stable for closer tip-sample distances, but one can place the front atom of the metal tip inside the corral and investigate the change of the corral states with STM. The response of the states to this additional adatom indicates the expected repulsive force.
[1] Crommie et al. Science 262, 218 (1993)