Effective Kondo model for a trimer on a metallic surface

A. A. ALIGIA

PHYSICAL REVIEW LETTERS

APS

Lugar: New York; Año: 2006 vol. 96 p. 96 - 804

0031-9007

I consider a Hubbard-Anderson model which describes localized orbitals in three different atoms hybridized both among themselves and with a continuum of extended states. Using a generalized Schrieffer-Wolf transformation, I derive an effective Kondo model for the interaction between the doublet ground state of the isolated trimer and the extended states. For an isoceles trimer with  distances a, l, l between the atoms, the Kondo temperature is very small for l < a and has a maximum for finite  l > a when a is small. The results agree with experiments for a Cr trimer on Au(111).