Combining the tight-binding approximation and linear elasticity theory for a
planar membrane, we investigate stretching of a graphene flake assuming that
two opposite edges of the sample are clamped by the contacts. We show that,
depending on the aspect ratio of the flake and its orientation, gapped states
may form in the membrane in the vicinity of the contacts. This gap in the
pre-contact region should be biggest for the armchair orientation of the flake
and width to length ratio of around 1.Comment: 7 pages + 3 figure