The effects of low-temperature illumination and annealing on fractional quantum Hall (FQH) characteristics of a GaAs/AlGaAs quantum well are investigated. Illumination alone, below 1 K, decreases the density of the two-dimensional electron gas (2DEG) electrons by more than an order of magnitude and resets the sample to a repeatable initial state. Subsequent thermal annealing at a few Kelvin restores the original density and dramatically improves FQH characteristics. A reliable illumination and annealing recipe is developed that yields an energy gap of 600 mK for the 5/2 state.
Physical Review B
- Pub Date:
- September 2014
- Electron states and collective excitations in multilayers quantum wells mesoscopic and nanoscale systems;
- Condensed Matter - Mesoscale and Nanoscale Physics
- Phys. Rev. B 90, 121405 (2014)