Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 46: Surface magnetism I (jointly with MA)

O 46.3: Talk

Wednesday, March 16, 2011, 11:45–12:00, CHE 184

First-principles study of the magnetic interaction in single atom contacts — •Cesar Lazo, Paolo Ferriani, and Stefan Heinze — Institute of Theoretical Physics and Astrophysics, University of Kiel, Germany

The miniaturization of spintronic devices towards the limit of single atoms calls for an understanding of the interaction and electron transport in atomic-scale contacts. Such structures are extreme cases, where the typical dimensions are comparable to the Fermi wavelength and a fully quantum mechanical description is required. Based on density functional theory calculations, we investigate single atom contacts formed by an antiferromagnetic Cr-tip of a scanning tunneling microscope (STM) and a magnetic atom adsorbed on a metallic surface. We analyze the exchange interaction between tip and adatom from the tunneling to the contact regime and explain a spin-valve effect observed with an STM [1]. Furthermore, we characterize the geometric properties of the contact as the tip approaches the sample, and show that the relaxations in the system can be related to the measured spin-polarization [1].

[1] M. Ziegler et al. in preparation