Abstract
The conductance of ballistic quantum constrictions in a two-dimensional electron gas has been studied experimentally as a function of the applied voltage. Large nonlinearities are found in the current-voltage characteristics. We give a simple model, which explains the main features of the nonlinear conductance. Breakdown of the conductance quantization occurs when the number of occupied one-dimensional subbands becomes unequal for the two velocity directions. A critical voltage is found for the breakdown, which is equal to the subband separation at the Fermi level.
- Received 12 December 1988
DOI:https://doi.org/10.1103/PhysRevB.39.8040
©1989 American Physical Society