Microscopic Theory of the Single Impurity Surface Kondo Resonance

Abstract

We develop a microscopic theory of the single impurity Kondo effect on a metallic surface. We calculate the hybridization energies for the Anderson Hamiltonian of a magnetic impurity interacting with surface and bulk states and show that, contrary to the Kondo effect of an impurity in the bulk, the hybridization matrix elements are strongly dependent on the momentum around the Fermi surface. Furthermore, by calculating the tunneling conductance of a scanning tunneling microscope (STM), we show that when the magnetic impurity is located at a surface the Kondo effect can occur with equal strength between bulk and surface states. We compare our results with recent experiments of Co impurities in Cu(111) and Cu(100) surfaces and find good quantitative agreement.

New version of the original manuscript with extended discussions on the problem of wavefunction orthogonality, the limitations of the theory, more figures related to the STM experiments, and one correction to an earlier result. Accepted for publication in Phys.Rev.B