Physics of a few magnetic atoms adsorbed on a surface

F. Delgado^1,2 and J. Fernández-Rossier³

¹Material Physics Center, Manuel de Lardizabal 5, Guipúzcoa E-20018 (SPAIN)

² IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain.

³ International Iberian Nanotechnology Laboratory, Avn.Mestre José Veiga, 4715-330 Braga, Portugal

 

Single magnetic atoms adsorbed on surfaces are likely the ultimate limit of magnetic storage and processing devices [1], and they serve as controllable systems where the  quantum character of magnets emerges. These characteristics have foster both, the experimental and theoretical study, going from the role of the magnetic anisotropy, the dissipative dynamics associated with the coupling to the substrate or the formation of a many body singlet state, the so called Kondo effect.  From the experimental point of view, the Scanning Tunneling Microscope (STM) makes it possible to fabricate and probe magnetic nanostructures with atomic resolution, going from individual atoms up to arrays of spin chains [2].

 

The theoretical description of these magnetic adsorbates requires to deal with both, the quantum nature and the dissipative coupling to the environment. While the first can be accounted for by an effective spin Hamiltonian [2-3], the energy and momentum transfer can be described by an exchange coupling with the adsorbate spins [3]. A perturbative treatment of the coupling has successfully explained the experimentally measured spectral features [2,4,5], the magnetoresistive response or the spatial variations of the spin waves [6].

 

 

 

References

       [1]         R. Wiesendanger, Rev. Mod. Phys. 81, 1495 (2009)

       [2]         S. Loth, S. Baumann, C. P. Lutz et al., Sience 335, 196 (2012)

       [3]            F. Delgado and J. Fernández-Rossier, Phys. Rev. B 82, 134414 (2010)

       [4]         J. C. Oberg, M. R. Calvo, F. Delgado et al., Nature Nanotechnology 9, 64 (2014).

       [5]         A. Spinelly, B.  Bryant, F. Delgado et al., Nature Materials 13, 782 (2014)