ARTIFICIAL IMPURITIES IN QUANTUM WIRES - FROM CLASSICAL TO QUANTUM BEHAVIOR

We have introduced a controllable artificial impurity or ''antidot'' into a quantum wire and report on the novel phenomena observed as this system evolves from classical behavior at low magnetic fields to the quantum Hall regime. In the transition, conductance resonances due to magnetically bound impurity states are detected. The resonant oscillations exhibit beating and sharp period changes. A theoretical model based on an interedge state coupling mechanism and a new nonlocal effect of edge state formation at local potential energy maxima account for the principal experimental features.