Strong negative differential resistance in graphene devices with local strain

The effects of local uniaxial strain on grapshene devices like single-barrier structure and p-n tunnel diode are investigated. The strain-induced displacement of Dirac points allows us toi suppress and/or control the Klein tunneling and the interband tunneling, which leads to strong effect of negative differential conductance. It is shown that when strain is suitably applied, the peak-to-valley ratio of the current-voltage characteristics can reach of a few hundred at room temperature.