Strain effects on the electronic properties of devices made of twisted graphene layers

The effects of uniaxial strain on the electronic and transport properties of twisted graphene bilayer structures are investigated by means of atomistic simulation. It is shown that the strain-induced modulation of band structure makes it possible to break the degeneracy and to modulate the position van Hove singularities. It is even possible to observe low-energy saddle points for a large range of twist angles. It is shown also that the strain-induced separation of Dirac points of the two lattices may generate a finite transport gap as large as a few hundreds of meV for a small strain of a few percent.