  Structural, energetic and tribological characteristics of double-layer
graphene with commensurate and incommensurate krypton spacers of nearly
monolayer coverage are studied within the van der Waals-corrected density
functional theory. It is shown that when the spacer is in the commensurate
phase, the graphene layers have the AA stacking. For this phase, the barriers
to relative in-plane translational and rotational motion and the shear mode
frequency of the graphene layers are calculated. For the incommensurate phase,
both of the barriers are found to be negligibly small. A considerable change of
tunneling conductance between the graphene layers separated by the commensurate
krypton spacer at their relative subangstrom displacement is revealed by the
use of the Bardeen method. The possibility of nanoelectromechanical systems
based on the studied tribological and electronic properties of the considered
heterostructures is discussed.
