TY - JOUR
T1 - Structure and local variations of the graphene moiré on Ir(111)
AU - Hämäläinen, Sampsa K.
AU - Boneschanscher, Mark P.
AU - Jacobse, Peter H.
AU - Swart, Ingmar
AU - Pussi, Katariina
AU - Moritz, Wolfgang
AU - Lahtinen, Jouko
AU - Liljeroth, Peter
AU - Sainio, Jani
PY - 2013/11/22
Y1 - 2013/11/22
N2 - We have studied the incommensurate moiré structure of epitaxial graphene grown on iridium(111) by dynamic low-energy electron diffraction [LEED I(V)] and noncontact atomic force microscopy (AFM) with a CO-terminated tip. Our LEED I(V) results yield the average positions of all the atoms in the surface unit cell and are in qualitative agreement with the structure obtained from density functional theory. The AFM experiments reveal local variations of the moiré structure: The corrugation varies smoothly over several moiré unit cells between 42 and 56 pm. We attribute these variations to the varying registry between the moiré symmetry sites and the underlying substrate. We also observe isolated outliers, where the moiré top sites can be offset by an additional 10 pm. This study demonstrates that AFM imaging can be used to directly yield the local surface topography with pm accuracy even on incommensurate two-dimensional structures with varying chemical reactivity.
AB - We have studied the incommensurate moiré structure of epitaxial graphene grown on iridium(111) by dynamic low-energy electron diffraction [LEED I(V)] and noncontact atomic force microscopy (AFM) with a CO-terminated tip. Our LEED I(V) results yield the average positions of all the atoms in the surface unit cell and are in qualitative agreement with the structure obtained from density functional theory. The AFM experiments reveal local variations of the moiré structure: The corrugation varies smoothly over several moiré unit cells between 42 and 56 pm. We attribute these variations to the varying registry between the moiré symmetry sites and the underlying substrate. We also observe isolated outliers, where the moiré top sites can be offset by an additional 10 pm. This study demonstrates that AFM imaging can be used to directly yield the local surface topography with pm accuracy even on incommensurate two-dimensional structures with varying chemical reactivity.
UR - http://www.scopus.com/inward/record.url?scp=84890470238&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.88.201406
DO - 10.1103/PhysRevB.88.201406
M3 - Article
AN - SCOPUS:84890470238
SN - 1098-0121
VL - 88
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 20
M1 - 201406
ER -