Strong correlation effects in theoretical STM studies of magnetic adatoms

Abstract

We present a theoretical study for the scanning tunneling microscopy (STM) spectra of surface-supported magnetic nanostructures, incorporating strong correlation effects. As concrete examples, we study Co and Mn adatoms on the Cu(111) surface, which are expected to represent the opposite limits of the Kondo physics and local moment behavior, using a combination of density functional theory and both quantum Monte Carlo and exact diagonalization impurity solvers. We examine in detail the effects of temperature $T$, correlation strength $U$, and the impurity $d$ electron occupancy $N_d$ on the local density of states. We also study the effective coherence energy scale, i.e., the Kondo temperature $T_K$, which can be extracted from the STM spectra. Theoretical STM spectra are computed as a function of the STM tip position relative to each adatom. Because of the multi-orbital nature of the adatoms, the STM spectra are shown to consist of a complicated superposition of orbital contributions, with different orbital symmetries, self-energies and Kondo temperatures. For the Mn adatom, which is close to half-filling, the STM spectra are featureless near the Fermi level. On the other hand, the quasiparticle peak for Co adatom gives rise to strongly position-dependent Fano line-shapes.

16 pages, 13 figures

References in corpus (19)

• Continuous-time Monte Carlo methods for quantum impurity models
• Strong electronic correlations from Hund's coupling
• TRIQS: A Toolbox for Research on Interacting Quantum Systems
• TRIQS/CTHYB: A Continuous-Time Quantum Monte Carlo Hybridization Expansion Solver for Quantum Impurity Problems
• The coherence-incoherence crossover and the mass-renormalization puzzles in Sr2RuO4
• Spin Excitations and Correlations in Scanning Tunneling Spectroscopy
• Long-range Kondo signature of a single magnetic impurity
• Computing total energies in complex materials using charge self-consistent DFT+DMFT
• Kondo resonance narrowing in d- and f-electron systems
• Tuning emergent magnetism in a Hund's impurity
• Interplay between Kondo effect and Ruderman-Kittel-Kasuya-Yosida interaction
• The Spin-Polarization of the Split Kondo State
• Towards a full ab initio theory of strong electronic correlations in nanoscale devices
• Density functional plus dynamical mean field theory of the metal-insulator transition in early transition metal oxides
• Mapping Itinerant Electrons around Kondo Impurities
• Orbital signatures of Fano-Kondo line shapes in STM adatom spectroscopy
• Renormalization of electron self-energies via their interaction with spin excitations: A first-principles investigation
• Co adatoms on Cu surfaces: ballistic conductance and Kondo temperature
• Orbital dependent electron tunneling within the atom superposition approach: Theory and application to W(110)

Cited by in corpus (12)

• Spin decoherence of magnetic atoms on surfaces
• Quantum transport simulation scheme including strong correlations and its application to organic radicals adsorbed on gold
• Adaptively truncated Hilbert space based impurity solver for dynamical mean-field theory
• Low-energy physics of three-orbital impurity model with Kanamori interaction
• From tunneling to contact in a magnetic atom: the non-equilibrium Kondo effect
• Renormalization of single-ion magnetic anisotropy in the absence of Kondo effect
• A new view on the origin of zero-bias anomalies of Co atoms atop noble metal surfaces
• Simulation of inelastic spin flip excitations and Kondo effect in STM spectroscopy of magnetic molecules on metal substrates
• Longitudinal and transverse spin relaxation times of magnetic single adatoms: an ab initio analysis
• Kondo screening in Co adatoms with full Coulomb interaction
• Anomalous excitations of atomically crafted quantum magnets
• Surface states influence in the conductance spectra of Co adsorbed on Cu(111)