Directed growth of hydrogen lines on graphene: High-throughput simulations powered by evolutionary algorithm

G. Özbal, J.T. Falkenberg, M. Brandbyge, R. T. Senger, H. Sevincli*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

244 Downloads (Pure)

Abstract

We set up an evolutionary algorithm combined with density functionaltight-binding (DFTB) calculations to investigate hydrogen adsorption on flatgraphene and graphene monolayers curved over substrate steps. During theevolution, candidates for the new generations are created by adsorption of anadditional hydrogen atom to the stable configurations of the previousgeneration, where a mutation mechanism is also incorporated. Afterwards atwo-stage selection procedure is employed. Selected candidates act as theparents of the next generation. In curved graphene, the evolution follows asimilar path except for a new mechanism, which aligns hydrogen atoms on theline of minimum curvature. The mechanism is due to the increased chemicalreactivity of graphene along the minimum radius of curvature line (MRCL) and to sp3 bond angles being commensurate with the kinked geometry of hydrogenatedgraphene at the substrate edge. As a result, the reaction barrier is reducedconsiderably along the MRCL, and hydrogenation continues like a mechanicalchain reaction. This growth mechanism enables lines of hydrogen atoms along theMRCL, which has the potential to overcome substrate or rippling effects andcould make it possible to define edges or nanoribbons without actually cuttingthe material.
Original languageEnglish
Article number073406
JournalPhysical Review Materials
Volume2
Issue number7
Number of pages10
ISSN2475-9953
DOIs
Publication statusPublished - 2018

Cite this