EFFECTS OF GEOMETRY AND POTENTIAL PROFILE ON NONLINEAR TRANSPORT IN NARROW BALLISTIC CONSTRICTIONS

We present quantum-mechanical model calculations of nonlinear transport in a ballistic quasi-one-dimensional (1D) channel. The effects of the geometry and potential profile on the quantum conductance for 1D ballistic transport through a constriction in a quasi-two-dimensional electron gas (2DEG) are investigated. It is found that the effects of the confining electrostatic potential in the channel on conductance are significant for large biases. To determine the nonlinear transport properties it is essential to consider how the voltage is dropped along the constriction. The appearance of new plateaux in the differential conductance of a ballistic 1D channel in the high-bias regime is possible, but depends on the form of the constriction.