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MA: Fachverband Magnetismus

MA 4: Surface Magnetism I

MA 4.1: Vortrag

Montag, 23. März 2009, 11:00–11:15, HSZ 403

Spin-resolved excitations of single atoms with STM — •Kirsten von Bergmann^1,2, Sebastian Loth¹, Markus Ternes¹, Alexander F. Otte^1,3, Cyrus F. Hirjibehedin^1,4, Christopher P. Lutz¹, and Andreas J. Heinrich¹ — ¹IBM Almaden Research Center — ²University of Hamburg — ³NIST Gaithersburg — ⁴London Centre for Nanotechnology

STM with its high lateral resolution can be used to obtain information about magnetic properties in two ways: inelastic tunneling spectroscopy has been shown to enable spin flip excitations in single atoms [1], while spin-polarized STM has been used to study ground state properties of nanoscale structures [2].

We have combined these two approaches to gain further insight by using a spin-polarized STM tip to excite the spin of single Co atoms on a thin insulating layer of Cu₂N on Cu(001). While spin-averaged measurements on this system yield the energy of spin-flip transitions [3], the spin-resolved data enables the determination of the character of the observed excitations. The degree of spin polarization is compared to calculations within the Heisenberg model. Since the Co atom shows the Kondo effect in this environment, this measurement provides additional information about the spin polarization of the Kondo resonance, which is split in an external magnetic field.

[1] A.J. Heinrich et al., Science 306, 466 (2004).

[2] M. Bode, Rep. Prog. Phys. 66, 523 (2003).

[3] A.F. Otte et al., Nature Phys. 4, 847 (2008).