Nonlinear Response of a Clean One-Dimensional Wire

The nonlinear transport in a clean one-dimensional wire fabricated by cleaved edge overgrowth (CEO) in molecular beam epitaxy was studied. A feature in the differential conductance similar to the '0.7 structure', found in quantum point contact (QPC) devices, was observed. A link between this phenomenon, charge neutrality and unidirectional dynamics in the wire was suggested using a simple model. The results show that at low temperatures '0.7 structure' occurs whenever the applied bias is as large as 4 times the Fermi energy in the wire.