Effect of RKKY Interaction on the Scanning Tunneling Spectra of a Classic Kondo System-Two Magnetic Atoms Adsorbed on a Metal Surface-

摘要

We calculate the corresponding differential conductance (dI/dV) spectra from scanning tunneling spectroscopy (STS) measurements for two magnetic atoms adsorbed on a metal surface. The formula for the dI/dV spectra is based on a model that explicitly takes into account the energy dependence of the electron tunneling matrices between the corresponding constituent components, viz., the magnetic adatoms and metal surface. We find that the shape of the dI/dV spectra varies with the distance between the two magnetic adatoms. From considerations of the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction strength on the metal surface, we conclude that the ferromagnetic RKKY interaction sharpens the dI/dV peak structure, making it more pronounced. On the other hand, the antiferromagnetic RKKY interaction broadens the peak structure. This result agrees well with experimental results and confirms that the RKKY interaction causes the deformation of the observed STS peak structure.