PHASE COHERENCE AND TRAJECTORY TRAPPING AROUND ONE OR 2 INDEPENDENTLY CONTROLLABLE ANTIDOTS IN QUANTUM WIRES

Magnetoconductance measurements have been made on an interesting versatile system. Six independent gates, on a two-dimensional electron-gas heterostructure, are used to define electrostatically two independently controllable antidots within a quantum wire. Measurements in a magnetic field show trapping of trajectories around either a single or a pair of antidots. Collimation, adiabatic transport, and trapping effects combine to create a rich variety of magnetoconductance features which are modulated by large single-period Aharonov-Bohm oscillations at temperatures below 1 K. Experimental features are compared to results from semiclassical ballistic-trajectory models and the similarities and differences between this system and antidot lattices discussed. © 1995 The American Physical Society.