Frustrated magnetic clusters on metallic surfaces
Abstract
Studies of small clusters of magnetic adatoms on metallic surfaces can be used to explore the physics that will dominate future magnetic nanodevices. Jamneala et al. [1] found that the scanning tunneling microscopy spectrum taken above an antiferromagnetically coupled Cr trimer on gold was sensitive to the cluster geometry: a sharp Kondo resonance observed for equilateral trimers had no counterpart for isosceles trimers. This result has been interpreted [2] using a variational ground state composed from states in which two Cr moments form a spin singlet, while the third is Kondo-screened. I will report a study of a Kondo model for an equilateral trimer, using a combination of numerical renormalization-group and algebraic methods, that points to a very different ground state: the local moments lock themselves into a frustrated spin doublet, which is then collectively screened by the conduction electrons. This unconventional Kondo effect is accompanied by non-Fermi-liquid behavior of the conduction electrons. Experimental signatures of this state will be discussed. [1ex] [1] T. Jamneala et al., Phys. Rev. Lett. 87, 256804 (2001). [2] Yu. B. Kudasov and V. M. Uzdin, Phys. Rev. Lett. 89, 276802 (2002).
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARU20005I