Related papers: The effective Kondo model for a trimer on a metall…
The electronic properties and spectroscopic features of a magnetic trimer with a Kondo-like coupling to a non-magnetic metallic substrate are analyzed at zero temperature. The substrate density of states is depressed in the trimer…
Motivated by the recent experiments of Jamneala {\em et al.} [T. Jamnaela {\em et al.}, Phys. Rev. Lett. {\bf 87}, 256804 (2001)], by combining {\em ab-initio} and renormalization group methods, we study the strongly correlated state of a…
Co single atom junctions on copper surfaces are studied by scanning tunneling microscopy and ab-initio calculations. The Kondo temperature of single cobalt atoms on the Cu(111) surface has been measured at various tip-sample distances…
We have carried out collinear and non-collinear electronic structure calculations to investigate the structural, electronic and magnetic properties of isolated Cr atoms, dimers and compact trimers. We find that the Cr monomer prefers to…
We study strongly correlated states in triangular artificial atoms. Symmetry-driven orbital degeneracy of the single particle states can give rise to an SU(4) Kondo state with entangled orbital and spin degrees of freedom, and a…
In this Thesis we develop a novel direction in the theory of nano-objects, i.e., structures of nanometer size in a tunnel contact with macroscopic electron reservoirs (metallic leads). In particular we elucidate the Kondo effect predicted…
We discuss a model Kondo-type Hamiltonian representing an analytically tractable version of the model used by Yin {\it et.al.}, Phys. Rev. B{\bf 86}, 2399 (2012) to explain the non-Fermi liquid behavior of iron chalcogenides and ruthenates…
The method of continuous unitary transformations (CUTs) is applied to the Anderson impurity and the Kondo model aiming at the systematic derivation of convergent effective models. If CUTs are applied in a conventional way, diverging…
Based on the experimental observation, that only the close vicinity of a magnetic impurity at metal surfaces determines its Kondo behaviour, we introduce a simple model which explains the Kondo temperatures observed for cobalt adatoms at…
We investigate the properties of the molecular quantum dot (Holstein-Anderson) model using numerical and analytical techniques. Path integral Monte Carlo simulations for the cumulants of the distribution function of the phonon coordinate…
Impurity four- and six-level Kondo model, in which an ion is tunneling among four- and six-stable points and interacting with surrounding conduction electrons, are investigated by using the perturbative and numerical renormalization group…
We reinvestigate the large degeneracy solution of the multichannel Kondo problem, and show how in the universal regime the complicated integral equations simplifying the problem can be mapped onto a first order differential equation. This…
We consider an open quantum system in contact with fermionic metallic reservoirs in a nonequilibrium setup. For the case of spin, orbital or potential fluctuations, we present a systematic formulation of real-time renormalization group at…
Two magnetic atoms, one attached to the tip of a Scanning Tunneling Microscope (STM) and one adsorbed on a metal surface, each constituting a Kondo system, have been proposed as one of the simplest conceivable systems potentially exhibiting…
We consider a two dimensional Kondo lattice model with exchange J and hopping t in which three out of four impurity spins are removed in a regular way. At the particle-hole symmetric point the model may be studied with auxiliary field…
We study the effect of crystal field anisotropy in the underscreened $S=1$ Kondo lattice model. Starting from the two orbital Anderson lattice model and including a local anisotropy term, we show, through Schrieffer-Wolff transformation,…
The metallic phase of the two-orbital Anderson lattice is study in the limit of infinite spatial dimensions, where a second order perturbation treatment is used to solve the single-site problem. Using this approximation, in the Kondo…
The (111) surface of Cu, Ag and Au is characterized by a band of surface Shockley states, with constant density of states beginning slightly below the Fermi energy. These states as well as bulk states hybridize with magnetic impurities…
The magnetic susceptibility and susceptibility anisotropy of the quasi-binary alloy system Ce(x)La(1-x)Cu(2.05)Si(2) have been studied for low concentration of Ce ions. The single-ion desc ription is found to be valid for x < 0.1. The…
We investigate the transport through a nanoscale device consisting of a degenerate double-orbital Anderson dot coupled to two uncorrelated leads. We determine the thermoelectric transport properties close to the one-electron regime and…