Impact of local stacking on the graphene-impurity interaction: theory and experiments

Abstract

We investigate the graphene-impurity interaction problem by combining experimental - scanning tunneling microscopy (STM) and spectroscopy (STS) - and theoretical - Anderson impurity model and density functional theory (DFT) calculations - techniques. We use graphene on the SiC(000-1)(2x2)_C reconstruction as a model system. The SiC substrate reconstruction is based on silicon adatoms. Graphene mainly interacts with the dangling bonds of these adatoms which act as impurities. Graphene grown on SiC(000-1)(2x2)_C shows domains with various orientations relative to the substrate so that very different local graphene/Si adatom stacking configurations can be probed on a given grain. The position and width of the adatom (impurity) state can be analyzed by STM/STS and related to its local environment owing to the high bias electronic transparency of graphene. The experimental results are compared to Anderson's model predictions and complemented by DFT calculations for some specific local environments. We conclude that the adatom resonance shows a smaller width and a larger shift toward the Dirac point for an adatom at the center of a graphene hexagon than for an adatom just on top of a C graphene atom.

13 pages, 6 figures, Accepted for publication in Phys. Rev. B

References in corpus (10)

• The electronic properties of graphene
• Ultrahigh electron mobility in suspended graphene
• Detection of Individual Gas Molecules Absorbed on Graphene
• Spin-half paramagnetism in graphene induced by point defects
• Electrically tunable quantum anomalous Hall effect in 5d transition-metal adatoms on graphene
• Electron states of mono- and bilayer graphene on SiC probed by STM
• Localized Magnetic States in Graphene
• Imaging the interface of epitaxial graphene with silicon carbide via scanning tunneling microscopy
• Kondo Quantum Criticality of Magnetic Adatoms in Graphene
• Theory of Scanning Tunneling Spectroscopy of Magnetic Adatoms in Graphene

Cited by in corpus (4)

• Atomic and Electronic Structure of Si Dangling Bonds in Quasi-Free-Standing Monolayer Graphene
• Revealing the nature of defects in quasi free standing mono-layer graphene on SiC(0001) by means of Density Functional Theory
• Moiré-induced bandgap tuning by varying electric dipole in InSe/CuSe vertical heterostructure
• The graphene sheet versus the 2DEG: a relativistic Fano spin-filter via STM and AFM tips