Adsorption of group IV elements on graphene, silicene, germanene and stanene: dumbbell formation
Date
2014-12-09Source Title
Journal of Physical Chemistry C
Print ISSN
1932-7447
Publisher
ACS Publications
Volume
119
Issue
1
Pages
845 - 853
Language
English
Type
ArticleItem Usage Stats
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Abstract
Silicene and germanene derivatives constructed from periodic dumbbell units play a crucial role
in multilayers of these honeycomb structures. Using first-principles calculations based on density
functional theory, here we investigate the dumbbell formation mechanisms and energetics of Group IV
atoms adsorbed on graphene, silicene, germanene and stanene monolayer honeycomb structures. The
stabilities of the binding structures are further confirmed by performing ab-initio molecular dynamics
calculations at elevated temperatures, except for stanene which is subject to structural instability upon
the adsorption of adatoms. Depending on the row number of the adatoms and substrates we find three
types of binding structures, which lead to significant changes in the electronic, magnetic, and optical
properties of substrates. In particular, Si, Ge and Sn adatoms adsorbed on silicene and germanene
form dumbbell structures. Furthermore, dumbbell structures occur not only on single layer, monatomic
honeycomb structures, but also on their compounds like SiC and SiGe. We show that the energy barrier
to the migration of a dumbbell structure is low due to the concerted action of atoms. This renders
dumbbells rather mobile on substrates to construct new single and multilayer Si and Ge phases.
Keywords
AdatomsAdsorption
Binding Energy
Calculations
Density Functional Theory
Germanium
Graphene
Honeycomb Structures
Molecular Dynamics
Multilayers
Optical Properties
Silicon
Silicon Carbide Ab Initio Molecular Dynamics
Elevated Temperature
First-principles Calculation
Formation Mechanism
Germanene
Group Iv Atom
Single Layer
Structural Instability