We report the first observation of deviaton of the i=4 quantum Hall plateau from its quantized value, in narrow GaAs-AlxGa1-xAs quasi-1-d wires of width 2000A. The deviation arises in the form of aperiodic fluctuations as the magnetic field is varied, even though a deep minimum developes in longitudinal resistance. The fluctuation size grows with decreasing temperature and can be as large as 250Ω at 50mK. We suggest the observations arise from a combination of localization and Aharonov-Bohm quantum interference effects.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Materials Chemistry