Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 37: Joint Session "Surface Magnetism II" (jointly with O)

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) [1] instead of the regular value of 2 which is observed for the Cu(111) substrate [2]. 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.

[1] B. Chilian et al., Phys. Rev. B, accepted (2011).

[2] A. A. Khajetoorians et al., Phys. Rev. Lett. 106, 037205 (2011).