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Fig. S1. STM/AFM images of the graphene/Ir(111) system obtained via switching between CC STM and ... more Fig. S1. STM/AFM images of the graphene/Ir(111) system obtained via switching between CC STM and CFS AFM modes "on-the-fly". Scanning parameters: (a) STM: U T = +461 meV, I T = 7.6 nA, AFM: ∆f = −675 mHz (attractive regime), (b) STM: U T = −201 meV, I T = 7.6 nA, AFM: ∆f = +675 mHz (repulsive regime).

Scientific Reports, 2013

Realization of graphene moiré superstructures on the surface of 4d and 5d transition metals offer... more Realization of graphene moiré 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 moiré supercell, which determine the adsorption sites for molecules or metal clusters on graphene/Ir(111).

Physical Review Letters, 2011

Small clusters of Pt adatoms grown on Pt(111) exhibit a preference for the formation of linear ch... more Small clusters of Pt adatoms grown on Pt(111) exhibit a preference for the formation of linear chains, which cannot be explained by simple diffusion-limited aggregation. Density functional theory calculations show that short chains are energetically favorable to more compact configurations due to strong directional bonding by d z 2 -like orbitals, explaining the stability of the chains. The formation of the chains is governed by substrate distortions, leading to funneling towards the chain ends.

Physical Review B, 2011

ABSTRACT The adsorption of graphene on Ni(111) has been investigated on the basis of the adiabati... more ABSTRACT The adsorption of graphene on Ni(111) has been investigated on the basis of the adiabatic-connection fluctuation-dissipation theorem in the random phase approximation (RPA). Although we find a significant hybridization between the graphene π orbitals and Ni dz2 states at a binding distance of 2.17 Å, the adsorption energy is still in the range of a typical physisorption (67 meV per carbon). An important contribution to the energy is related to a decrease in the exchange energy resulting from the adsorption-induced lower symmetry in the graphene layer. The energetics can be well reproduced using the computationally significantly cheaper van der Waals density functional theory with an appropriately chosen exchange-correlation functional.

The Journal of Physical Chemistry Letters, 2012

... Gareth S. Parkinson‡, Michael Schmid‡, Roman Caudillo§, Florian Mittendorfer‡, Josef Redinger... more ... Gareth S. Parkinson‡, Michael Schmid‡, Roman Caudillo§, Florian Mittendorfer‡, Josef Redinger‡, and Ulrike Diebold‡. ... D. Usachov, O. Vilkov, A. Grüneis, D. Haberer, A. Fedorov, VK Adamchuk, AB Preobrajenski, P. Dudin, A. Barinov, M. Oehzelt, C. Laubschat, and DV Vyalikh. ...

ACS Nano, 2012

Graphene has a close lattice match to the Ni(111) surface, resulting in a preference for 1 × 1 co... more Graphene has a close lattice match to the Ni(111) surface, resulting in a preference for 1 × 1 configurations. We have investigated graphene grown by chemical vapor deposition (CVD) on the nickel carbide (Ni(2)C) reconstruction of Ni(111) with scanning tunneling microscopy (STM). The presence of excess carbon, in the form of Ni(2)C, prevents graphene from adopting the preferred 1 × 1 configuration and leads to grain rotation. STM measurements show that residual Ni(2)C domains are present under rotated graphene. Nickel vacancy islands are observed at the periphery of rotated grains and indicate Ni(2)C dissolution after graphene growth. Density functional theory (DFT) calculations predict a very weak (van der Waals type) interaction of graphene with the underlying Ni(2)C, which should facilitate a phase separation of the carbide into metal-supported graphene. These results demonstrate that surface phases such as Ni(2)C can play a major role in the quality of epitaxial graphene.

Fig. S1. STM/AFM images of the graphene/Ir(111) system obtained via switching between CC STM and ... more Fig. S1. STM/AFM images of the graphene/Ir(111) system obtained via switching between CC STM and CFS AFM modes "on-the-fly". Scanning parameters: (a) STM: U T = +461 meV, I T = 7.6 nA, AFM: ∆f = −675 mHz (attractive regime), (b) STM: U T = −201 meV, I T = 7.6 nA, AFM: ∆f = +675 mHz (repulsive regime).

Scientific Reports, 2013

Realization of graphene moiré superstructures on the surface of 4d and 5d transition metals offer... more Realization of graphene moiré 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 moiré supercell, which determine the adsorption sites for molecules or metal clusters on graphene/Ir(111).

Physical Review Letters, 2011

Small clusters of Pt adatoms grown on Pt(111) exhibit a preference for the formation of linear ch... more Small clusters of Pt adatoms grown on Pt(111) exhibit a preference for the formation of linear chains, which cannot be explained by simple diffusion-limited aggregation. Density functional theory calculations show that short chains are energetically favorable to more compact configurations due to strong directional bonding by d z 2 -like orbitals, explaining the stability of the chains. The formation of the chains is governed by substrate distortions, leading to funneling towards the chain ends.

Physical Review B, 2011

ABSTRACT The adsorption of graphene on Ni(111) has been investigated on the basis of the adiabati... more ABSTRACT The adsorption of graphene on Ni(111) has been investigated on the basis of the adiabatic-connection fluctuation-dissipation theorem in the random phase approximation (RPA). Although we find a significant hybridization between the graphene π orbitals and Ni dz2 states at a binding distance of 2.17 Å, the adsorption energy is still in the range of a typical physisorption (67 meV per carbon). An important contribution to the energy is related to a decrease in the exchange energy resulting from the adsorption-induced lower symmetry in the graphene layer. The energetics can be well reproduced using the computationally significantly cheaper van der Waals density functional theory with an appropriately chosen exchange-correlation functional.

The Journal of Physical Chemistry Letters, 2012

... Gareth S. Parkinson‡, Michael Schmid‡, Roman Caudillo§, Florian Mittendorfer‡, Josef Redinger... more ... Gareth S. Parkinson‡, Michael Schmid‡, Roman Caudillo§, Florian Mittendorfer‡, Josef Redinger‡, and Ulrike Diebold‡. ... D. Usachov, O. Vilkov, A. Grüneis, D. Haberer, A. Fedorov, VK Adamchuk, AB Preobrajenski, P. Dudin, A. Barinov, M. Oehzelt, C. Laubschat, and DV Vyalikh. ...

ACS Nano, 2012

Graphene has a close lattice match to the Ni(111) surface, resulting in a preference for 1 × 1 co... more Graphene has a close lattice match to the Ni(111) surface, resulting in a preference for 1 × 1 configurations. We have investigated graphene grown by chemical vapor deposition (CVD) on the nickel carbide (Ni(2)C) reconstruction of Ni(111) with scanning tunneling microscopy (STM). The presence of excess carbon, in the form of Ni(2)C, prevents graphene from adopting the preferred 1 × 1 configuration and leads to grain rotation. STM measurements show that residual Ni(2)C domains are present under rotated graphene. Nickel vacancy islands are observed at the periphery of rotated grains and indicate Ni(2)C dissolution after graphene growth. Density functional theory (DFT) calculations predict a very weak (van der Waals type) interaction of graphene with the underlying Ni(2)C, which should facilitate a phase separation of the carbide into metal-supported graphene. These results demonstrate that surface phases such as Ni(2)C can play a major role in the quality of epitaxial graphene.