2014/02/28 by Li Huang, Tim O. Wehling, Philipp Werner · 12 citations
Chemistry · Physics and Astronomy · #Anderson impurity model #Atom (system on chip) #Atomic physics #Chemistry #Condensed matter physics #Electron #Excitation #Ion #Ionization #Magnetic moment #Magnetic properties of thin films #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Quasiparticle #Spectral line #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.89.245104
published in Physical Review B 89(24) (American Physical Society) · 13 pages, 10 figures
arxiv created 2014/04/30 · openalex publication_date 2014/06/05 · arxiv updated 2014/12/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the competition of Coulomb interaction and hybridization effects in the five-orbital Anderson impurity model by means of continuous time quantum Monte Carlo, exact diagonalization, and Hartree-Fock calculations. The dependence of the electronic excitation spectra and thermodynamic ground-state properties on the hybridization strength and the form of the Coulomb interaction is systematically investigated for impurity occupation number N\ensuremath≈6. With increasing hybridization strength, a Kondo resonance emerges, broadens and merges with some of the upper and lower Hubbard peaks. Concomitantly, there is an increase of charge fluctuations at the impurity site. In contrast to the single-orbital model, some atomic multiplet peaks and exchange split satellites persist despite strong charge fluctuations. We find that Hund's coupling leads to a state that may be characterized as an itinerant single atom magnet. As the filling is increased, the magnetic moment decreases, but the spin freezing phenomenon persists up to N\ensuremath≈8. When the hybridization is weak, the positions of atomic ionization peaks are rather sensitive to shifts of the impurity on-site energies. This allows to distinguish atomic ionization peaks from quasiparticle peaks or satellites in the electronic excitation spectra. On the methodological side we show that a comparison between the spectra obtained from Monte Carlo and exact diagonalization calculations is possible if the charge fluctuations are properly matched.