The nature of bonding and electronic properties of graphene and benzene with iridium adatoms
- Author(s)
- Petr Lazar, Jaroslav Granatier, Jiri Klimes, Pavel Hobza, Michal Otyepka
- Abstract
Recent theoretical simulations predicted that graphene decorated with Ir
adatoms could realize a two-dimensional topological insulator with a
substantial band gap. Our understanding of how the electronic properties
of graphene change in the presence of metal adatoms is however still
limited, as the binding is quite complex involving static and dynamic
correlation effects together with relativistic contributions, which
makes the theoretical description of such systems quite challenging. We
applied the quantum chemical complete active space second order
perturbation theory (CASPT2) method and density functional theory beyond
the standard local density functional approach including relativistic
spin–orbit coupling (SOC) effects on Ir–benzene and Ir–graphene
complexes. The CASPT2-SOC method revealed a strong binding affinity of
Ir for benzene (33.1 kcal mol−1) at a 1.81 Å distance, which was of a single reference character, and a weaker binding affinity (6.3 kcal mol−1)
at 3.00 Å of a multireference character. In the Ir–graphene complex,
the quartet ground-state of the Ir atom changed to the doublet state
upon adsorption, and the binding energy predicted by optB86b-vdW-SOC
functional remained high (33.8 kcal mol−1). In
all cases the dynamic correlation effects significantly contributed to
the binding. The density of states calculated with the hybrid functional
HSE06 showed that the gap of 0.3 eV was induced in graphene by the
adsorbed Ir atom even in scalar relativistic calculation, in contrast to
metallic behaviour predicted by local density approximation. The
results suggest that the strong correlation effects contribute to the
opening of the band gap in graphene covered with the Ir adatoms. The
value of the magnetic anisotropy energy of 0.1 kcal mol−1 predicted by HSE06 is lower than those calculated using local functionals.
- Organisation(s)
- Computational Materials Physics
- External organisation(s)
- Czech Academy of Sciences, Slovak University of Technology in Bratislava, Palacký University Olomouc
- Journal
- Physical Chemistry Chemical Physics
- Volume
- 16
- Pages
- 20818-20827
- No. of pages
- 10
- ISSN
- 1463-9076
- DOI
- https://doi.org/10.1039/c4cp02608j
- Publication date
- 2014
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103025 Quantum mechanics, 103036 Theoretical physics, 103015 Condensed matter, 103009 Solid state physics
- Keywords
- ASJC Scopus subject areas
- General Physics and Astronomy, Physical and Theoretical Chemistry
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/9936f908-1d41-43b1-b8aa-51b4404fabf0