Orbitally controlled Kondo effect of Co adatoms on graphene

T. O. Wehling, A. V. Balatsky, M. I. Katsnelson, A. I. Lichtenstein, and A. Rosch
Phys. Rev. B 81, 115427 – Published 16 March 2010

Abstract

Based on ab initio calculations we identify possible scenarios for the Kondo effect due to Co adatoms on graphene. General symmetry arguments show that for magnetic atoms in high-symmetry positions, the Kondo effect in graphene is controlled not only by the spin but also by the orbital degree of freedom. For a Co atom absorbed on top of a carbon atom, the Kondo effect is quenched by spin-orbit coupling below an energy scale of 15K. For Co with spin S=1/2 located in the center of a hexagon, an SU(4) Kondo model describes the entanglement of orbital moment and spin at higher energies, while below 60meV spin-orbit coupling leads to a more conventional SU(2) Kondo effect. The interplay of the orbital Co physics and the peculiar band structure of graphene is directly accessible in Fourier transform tunneling spectroscopy or in the gate-voltage dependence of the Kondo temperature displaying a very strong, characteristic particle-hole asymmetry.

  • Figure
  • Figure
  • Figure
  • Figure
  • Received 10 February 2010

DOI:https://doi.org/10.1103/PhysRevB.81.115427

©2010 American Physical Society

Authors & Affiliations

T. O. Wehling1, A. V. Balatsky2,3, M. I. Katsnelson4, A. I. Lichtenstein1, and A. Rosch5

  • 1I. Institut für Theoretische Physik, Universität Hamburg, D-20355 Hamburg, Germany
  • 2Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
  • 3Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
  • 4Institute for Molecules and Materials, Radboud University Nijmegen, NL-6525 AJ Nijmegen, The Netherlands
  • 5Institute for Theoretical Physics, University of Cologne, 50937 Cologne, Germany

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 81, Iss. 11 — 15 March 2010

Reuse & Permissions
Access Options

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×