Speaker
Description
Electronic properties of graphene are sensitive to its environment and can be altered by adsorption of atomic clusters$^1$$^,$$^2$. These structure serves experimentally to probe the properties of the cluster and to tailor the properties of graphene$^2$$^,$$^3$. This work aims at studying the interaction between graphene and Au$_n$ (n=1-6) cluster using density functional theory calculations.
The structural study showed that clusters with n=1-6 Au atoms prefer to be in planar 2D geometries. From the electronic structure of Au$_n$/graphene system, it is found that cluster size plays a crucial role in the interaction between them. Gold clusters with an even number of atoms possess no charge transfer and no magnetic moment, whereas cluster with an odd number of atoms possess a magnetic moment of approximately 1 μ$_B$. There is also a net charge transfer between the cluster and graphene; n=1 and 5 results in p-type doping, whereas n=3 n-type doping, observed by shift in Fermi level from Dirac cone.
First-principles ballistic transport simulations have been performed on graphene adsorbed with Au$_3$ and Au$_6$ clusters. The current through the cluster decorated graphene is lower when compared with pristine graphene, indicating a reduced transmission and reduced mean-free path for backscattering in Au$_n$/graphene system.
The induced spin-orbit (SO) coupling strength by Au cluster on graphene has also been studied. It has been found that the SO coupling strength increases with the size of cluster, strength is enhanced from 9.8 meV to 15.6 meV for Au$_3$ and Au$_6$ cluster respectively. SO coupling strength is enhanced with increase in cluster density. The results obtained are in-line with experimentally observed doping. The trends observed for charge transport and SOC strength also serves as theoretical support for the experimental work.
Reference
[1]Y.Wu et al. small,20,3129-3136(2012).
[2]M.K.Srivastava et al. Phys.Rev.B,85,165444(2012)
[3]J.E.Scheerder et al. Adv.Mater.Interfaces,5,1801274(2018)
| Speaker Country | Belgium |
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