https://doi.org/10.1140/epjb/e2018-90141-6
Regular Article
Ab initio study of the (2 × 2) phase of barium on graphene★
1
Department of Physical and Chemical Sciences, University of L’Aquila,
Via Vetoio 10,
67100
L’Aquila, Italy
2
SPIN-CNR, University of L’Aquila,
Via Vetoio 10,
67100
L’Aquila, Italy
3
Sorbonne Université, Institut des Nanosciences de Paris, UMR7588,
75252
Paris, France
4
Faculty of Physics, University of Vienna,
Strudlhofgasse 4,
1090
Vienna, Austria
5
II. Physikalisches Institut, Universität zu Köln,
Zülpicher Straße 77,
50937
Cologne, Germany
6
Department of Materials Science, Moscow State University,
Leninskiye Gory 1/3,
119992
Moscow, Russia
a e-mail: gianni.profeta@aquila.infn.it
Received:
8
March
2018
Received in final form:
25
May
2018
Published online: 16
July
2018
We present a first-principles density functional theory study on the structural, electronic and dynamical properties of a novel barium doped graphene phase. Low energy electron diffraction of barium doped graphene presents clear evidence of (2 × 2) spots induced by barium adatoms with BaC8 stoichiometry. First principles calculations reveals that the phase is thermodynamically stable but unstable to segregation towards the competitive BaC6 monolayer phase. The calculation of phonon spectrum confirms the dynamical stability of the BaC8 phase indicating its metastability, probably stabilized by doping and strain conditions due to the substrate. Barium induces a relevant doping of the graphene π states and new barium-derived hole Fermi surface at the M-point of the (2 × 2) Brillouin zone. In view of possible superconducting phase induced by foreign dopants in graphene, we studied the electron–phonon coupling of this novel (2 × 2) obtaining λ = 0.26, which excludes the stabilization of a superconducting phase.
© EDP Sciences / Società Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature, 2018