High bias voltage transport in metallic single-walled carbon nanotubes under axial stress

We calculate the current-voltage characteristic of a homogeneously strained metallic carbon nanotube adsorbed on a substrate. The strain generates a gap in the energy spectrum leading to a reduction of the current. In the elastic regime, the current-voltage characteristic shows a large negative differential conductance at bias voltages of around greater than or similar to 0.17 V. We discuss the implications for the current in the superelongated regime.