FisMat2017 - Submission - View

Abstract's title: Frictional features in graphene nanoribbons deposited on gold
Submitting author: Lorenzo Gigli
Affiliation: SISSA - Internation School of Advanced Studies
Affiliation Address: Via Bonomea, 265, Trieste(TS)
Country: Italy
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Roberto Guerra, Nicola Manini, Andrea Benassi, Erio Tosatti, Andrea Vanossi

Via numerical simulations, we investigate the static structural features and the frictional response of armchair graphene nanoribbons (GNRs) of different lengths deposited on a gold Au(111) substrate, a tribilogical interface subject of recent, intense experimental studies. The C-Au lattice mismatch and the GNR-substrate relative orientation dictate the periodicity of the interface Moire' pattern for the relaxed GNR configurations. By adiabatically increasing an uniform external force directed along the longitudinal GNR axis, the molecular-dynamics approach shows a static frictional response which does not grow with the GNR length, thus supporting the experimental data of a superlubric behavior with negligible contribution of the internal bulk region of the ribbon. The peculiar oscillatory trend of the static friction versus length, around a fairly constant mean value (tens of pN), correlates with the characteristic modulation of the observed Moire' pattern.

Besides, trying to mimic the experimental framework by Kawai et al., we present preliminary results of the dynamical response of deposited GNRs, lifted at one end and pulled laterally by a spring moving at constant velocity. Competition between peeling and sliding mechanisms, stick-slip and smooth dynamics are discussed in terms of the edge-lifting height and the effective GNR elasticity.