BALLISTIC TRANSPORT IN ELECTRON-STUB-TUNER SUPERLATTICES

An electron stub tuner (EST) consists of a quantum wire to which is at tached a lateral branch or stub, of finite length that can be controll ed by a gate. The quantum interference between electron waves in the s tub and the wire makes the transmission, as a function the stub length , vary periodically between zero and one when one mode is present in t he wire. We consider superlattices composed of EST units and show hen; with a suitable choice of unit cell the transmission can have a form approaching: a square wave, which is desirable for applications such a s analog -to-digital converters. a unit cell composed of a double stub or crossbar geometry is particularly promising in this regard. We als o consider the multi-mode case and show how periodic patterns involvin g several transmission plateaus are possible.