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 $\gtrsim 0.17$V. We discuss the implications for the current in the superelongated regime.