Abstract
The conductance of a short, narrow ballistic constriction in a two-dimensional electron gas in a semiconductor heterostructure is calculated exactly for a simple but plausible model. A novel phenomenon is predicted: Such quantum channels should exhibit resonant conduction in highmobility samples at low temperatures. Their conductance should oscillate strongly as a function of Fermi level and gate voltage. This behavior can be used to measure directly the aspect ratio of the channels.