239 research outputs found
Preparation and photoemission investigation of bulk-like a-Mn films on W(110)
We report the successful stabilization of a thick bulk-like, distorted
-Mn film with (110) orientation on a W(110) substrate. The observed
overstructure for the Mn film with respect to the original W(110)
low-energy electron diffraction pattern is consistent with the presented
structure model. The possibility to stabilize such a pseudomorphic Mn film is
supported by density functional total energy calculations. Angle-resolved
photoemission spectra of the stabilized -Mn(110) film show weak
dispersions of the valence band electronic states in accordance with the large
unit cell.Comment: 11 pages; 5 figure
Graphene on ferromagnetic surfaces and its functionalization with water and ammonia
Here we present an angle-resolved photoelectron spectroscopy (ARPES), x-ray
absorption spec-troscopy (XAS), and density-functional theory (DFT)
investigations of water and ammonia ad-sorption on graphene/Ni(111). Our
results on graphene/Ni(111) reveal the existence of interface states,
originating from the strong hybridization of the graphene {\pi} and
spin-polarized Ni 3d valence band states. ARPES and XAS data of the H2O
(NH3)/graphene/Ni(111) system give an information about the kind of interaction
between adsorbed molecules and graphene on Ni(111). The presented experimental
data are compared with the results obtained in the framework of the DFT
approach.Comment: accepted in Nanoscale Research Letters; 16 pages, 4 figures, 2 table
Structural and electronic properties of the graphene/Al/Ni(111) intercalation-like system
Decoupling of the graphene layer from the ferromagnetic substrate via
intercalation of sp metal has recently been proposed as an effective way to
realize single-layer graphene-based spin-filter. Here, the structural and
electronic properties of the prototype system, graphene/Al/Ni(111), are
investigated via combination of electron diffraction and spectroscopic methods.
These studies are accompanied by state-of-the-art electronic structure
calculations. The properties of this prospective Al-intercalation-like system
and its possible implementations in future graphene-based devices are
discussed.Comment: 20 pages, 8 figures, and supplementary materia
Graphene on Rh(111): STM and AFM studies
The electronic and crystallographic structure of the graphene/Rh(111) moir\'e
lattice is studied via combination of density-functional theory calculations
and scanning tunneling and atomic force microscopy (STM and AFM). Whereas the
principal contrast between hills and valleys observed in STM does not depend on
the sign of applied bias voltage, the contrast in atomically resolved AFM
images strongly depends on the frequency shift of the oscillating AFM tip. The
obtained results demonstrate the perspectives of application atomic force
microscopy/spectroscopy for the probing of the chemical contrast at the
surface.Comment: manuscript and supplementary information; submitted to Appl. Phys.
Lett. on 01.03.201
Electronic structure, imaging contrast and chemical reactivity of graphene moir\'e on metals
Realization of graphene moir\'e superstructures on the surface of 4d and 5d
transition metals offers templates with periodically modulated electron
density, which is responsible for a number of fascinating effects, including
the formation of quantum dots and the site selective adsorption of organic
molecules or metal clusters on graphene. Here, applying the combination of
scanning probe microscopy/spectroscopy and the density functional theory
calculations, we gain a profound insight into the electronic and topographic
contributions to the imaging contrast of the epitaxial graphene/Ir(111) system.
We show directly that in STM imaging the electronic contribution is prevailing
compared to the topographic one. In the force microscopy and spectroscopy
experiments we observe a variation of the interaction strength between the tip
and high-symmetry places within the graphene moir\'e supercell, which determine
the adsorption cites for molecules or metal clusters on graphene/Ir(111).Comment: submitted on Sep, 6th 201
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