Abstract
We report magnetotransport measurements in a low-disorder three-layer electron system in a GaAs/As triple quantum-well structure. Fine adjustment of densities in different layers is achieved with the use of front and back gates and by monitoring the capacitance-voltage and low-field Shubnikov–de Haas data. At intermediate fields the diagonal resistance () shows strong minima at every third integer filling factor, ν=3, 6, 9, and 12, consistent with the subband structure. At higher fields, we observe deep minima at ν=7/5 and 5/7, suggesting anomalously strong 7/5 and 5/7 fractional quantum Hall states in this triple-layer system.
- Received 22 May 1992
DOI:https://doi.org/10.1103/PhysRevB.46.9776
©1992 American Physical Society