Stacking and band structure of van der Waals bonded graphane multilayers
We use density functional theory
and the van der Waals density functional (vdW-DF) method
to determine the binding separation in bilayer and bulk graphane
and study the corresponding electronic band structure.
The calculated binding separation (distance between center-of-mass planes)
and binding energy are 4.5-5.0 Å (4.5-4.8 Å) and 75-102 meV/cell (93-127 meV/cell)
in the bilayer (bulk), depending on the choice of vdW-DF version.
We obtain the corresponding band diagrams using ordinary GGA calculations
for the geometries specified by our vdW-DF results.
We find significant band-gap modifications by up to -1.2 eV (+4.0 eV)
in various regions of the Brillouin zone,
produced by the bilayer (bulk) formation.
The possibility of such large modifications signals
a potential of vdW-induced band-gap engineering in other materials
density functional theory
van der Waals