Berlin 2012 – wissenschaftliches Programm
MA 37.9: Vortrag
Donnerstag, 29. März 2012, 11:45–12:00, EB 301
Anomalously large g-factor of single atoms adsorbed on a metal substrate — •Jens Wiebe1, Alexander A. Khajetoorians1, Samir Lounis2, Antonio T. Costa3, Bruno Chilian1, Douglas L. Mills4, and Roland Wiesendanger1 — 1Institute of Applied Physics, Hamburg University, Germany — 2Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich, Germany — 3Instituto de Física, Universidade Federal Fluminense, Rio de Janeiro, Brazil — 4Department of Physics and Astronomy, University of California Irvine, USA
We performed magnetic field dependent inelastic scanning tunneling spectroscopy (ISTS) on individual Fe atoms adsorbed on different metal surfaces. ISTS reveals a spin excitation which is shifting linearly to higher energies in the magnetic field. The magnetic anisotropies and the g-factors of the Fe atoms, as well as the lifetimes of the excitations, are extracted. We find lifetimes of hundreds of fs limited by coupling to electron-hole pairs in the substrate and decreasing linearly in the magnetic field. As expected, the magnetic anisotropy strongly depends on the substrate. Astoundingly, the g-factor is g ≈ 3.1 for Ag(111)  instead of the regular value of 2 which is observed for the Cu(111) substrate . This very large g-shift can be understood when considering the complete electronic structure of both the Ag(111) surface state and the Fe atom, as shown by ab initio calculations of the magnetic susceptibility.
 B. Chilian et al., Phys. Rev. B, accepted (2011).
 A. A. Khajetoorians et al., Phys. Rev. Lett. 106, 037205 (2011).