Spectral evolution of the SU(4) Kondo effect from the single impurity to the two-dimensional lattice

Abstract

We describe the evolution of the SU(4) Kondo effect as the number of magnetic centers increases from one impurity to the two-dimensional (2D) lattice. We derive a Hubbard-Anderson model which describes a 2D array of atoms or molecules with two-fold orbital degeneracy, acting as magnetic impurities and interacting with a metallic host. We calculate the differential conductance, observed typically in experiments of scanning tunneling spectroscopy, for different arrangements of impurities on a metallic surface: a single impurity, a periodic square lattice, and several sites of a rectangular cluster. Our results point towards the crucial importance of the orbital degeneracy and agree well with recent experiments in different systems of iron(II) phtalocyanine molecules deposited on top of Au(111) [N. Tsukahara et al., Phys. Rev. Lett. 106, 187201 (2011)], indicating that this would be the first experimental realization of an artificial 2D SU(4) Kondo-lattice system.

17 pages, 4 figures. New version contains an Appendix with details of the derivation of the Hamiltonian Eq.(2), derivation of the slave-boson mean-field equations, and an estimation of the upper bounds of the RKKY interaction

References in corpus (10)

• Dependence of Single Molecule Junction Conductance on Molecular Conformation
• Orbital Kondo effect in carbon nanotubes
• Electronic and magnetic properties of molecule-metal interfaces: transition metal phthalocyanines adsorbed on Ag(100)
• Quantum phase transition in capacitively coupled double quantum dots
• Zero-bias conductance in carbon nanotube quantum dots
• Thermopower of an SU(4) Kondo resonance under an SU(2) symmetry-breaking field
• Non-Fermi liquid behavior in transport through Co doped Au chains
• Scanning tunneling microscopy of adsorbed molecules on metalic surfaces for nearly localized atomic states
• Two channel orbital Kondo effect in quantum dot with SO(n) symmetry
• Easy-axis ferromagnetic chain on a metallic surface

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• Restoring the SU(4) Kondo regime in a double quantum dot system
• Low-energy physics for an iron phthalocyanine molecule on Au(111)
• Spin and orbital ordering in bilayer Sr${}_3$Cr${}_2$O${}_7$
• Valence fluctuations in a lattice of magnetic molecules: application to iron(II) phtalocyanine molecules on Au(111)
• Two-stage three-channel Kondo physics for an FePc molecule on the Au(111) surface
• Kondo physics in a Ni impurity embedded in O-doped Au chains
• Structural and electrical characterization of the monolayer Kondo-lattice compound CePt${}_6$/Pt(111)
• Kondo temperature when the Fermi level is near a step in the conduction density of states
• Magnetic and orbital instabilities in a lattice of SU(4) organometallic Kondo complexes