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O: Fachverband Oberflächenphysik
O 50: [MA] Joint Session "Surface Magnetism I" (jointly with O)
O 50.11: Talk
Wednesday, March 28, 2012, 18:45–19:00, BH 243
How the local environment affects the magnetic anisotropy and Kondo Screening of a high-spin atom — •Jenny C. Oberg1,2, Reyes M. Calvo1, and Cyrus F. Hirjibehedin1,2,3 — 1London Centre for Nanotechnology, UCL, UK — 2Department of Physics and Astronomy, UCL, UK — 3Department of Chemistry, UCL, UK
We study the magnetic anisotropy and the Kondo screening of the spin of Co atoms on Cu2N using STM-based tunneling spectroscopy. We find that variations of the surface close to the edges of both small (ca 25nm2) and large (ca 400 nm2) Cu2N islands result in changes in both anisotropy and Kondo screening. For small Cu2N islands, we find that when the Co atoms are placed very close to the edges the Kondo screening weakens while the anisotropy increases in magnitude and changes its symmetry. Surprisingly, on larger Cu2N islands formed on supersaturated Cu2N surfaces, we find that a similar behavior occurs as the Co atoms move away from the edge of the islands: at the center of these large islands, Kondo screening is completely suppressed while the anisotropy energy is twice as large as at the edge of the islands. We examine possible causes for these dramatic changes in the Kondo screening and magnetic anisotropy, including a possible interaction with a quantum-confined surface state below the Cu2N.