Atomic Scale Identification of Coexisting Graphene Structures on Ni(111).
Through a combined scanning tunneling microscopy (STM) and density functional theory (DFT) approach, we provide a full characterization of the different chemisorbed configurations of epitaxial graphene coexisting on the Ni(111) single crystal surface. Top-fcc, top-hcp, and top-bridge are found to be stable structures with comparable adsorption energy. By comparison of experiments and simulations, we solve an existing debate, unambiguously distinguishing these configurations in high-resolution STM images and characterizing the transitions between adjacent domains. Such transitions, described in detail through atomistic models, occur not only via sharp domain boundaries, with extended defects, but predominantly via smooth in-plane distortions of the carbon network, without disruption of the hexagonal rings, which are expected not to significantly affect electron transport.
†Department of Physics, Università degli Studi di Trieste, via Alfonso Valerio 2, 34127 Trieste, Italy.
Federico
F
Bianchini
†Department of Physics, Università degli Studi di Trieste, via Alfonso Valerio 2, 34127 Trieste, Italy.|‡IOM-CNR Laboratorio TASC, Area Science Park, s.s. 14 km 163.5, Basovizza, 34149 Trieste, Italy.
Laerte L
LL
Patera
†Department of Physics, Università degli Studi di Trieste, via Alfonso Valerio 2, 34127 Trieste, Italy.|§IOM-CNR DEMOCRITOS Theory@Elettra Group, Sincrotrone Trieste, Area Science Park, s.s. 14 km 163.5, Basovizza, 34149 Trieste, Italy.|∥Consorzio Interuniversitario Nazionale per la Scienza e la Tecnologia dei Materiali (INSTM), Unità di ricerca di Trieste, piazzale Europa 1, 34128 Trieste, Italy.
Maria
M
Peressi
‡IOM-CNR Laboratorio TASC, Area Science Park, s.s. 14 km 163.5, Basovizza, 34149 Trieste, Italy.
Cristina
C
Africh
†Department of Physics, Università degli Studi di Trieste, via Alfonso Valerio 2, 34127 Trieste, Italy.|‡IOM-CNR Laboratorio TASC, Area Science Park, s.s. 14 km 163.5, Basovizza, 34149 Trieste, Italy.|⊥Center of Excellence for Nanostructured Materials (CENMAT), Università degli Studi di Trieste, via Alfonso Valerio 2, 34127 Trieste, Italy.
Giovanni
G
Comelli
Ni; atomic structure; density functional theory (DFT); graphene; scanning tunneling microscopy (STM)