Low-temperature illumination and annealing of ultrahigh quality quantum wells

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Low-temperature illumination and annealing of ultrahigh quality quantum wells

M. Samani, A. V. Rossokhaty, E. Sajadi, S. Lüscher, J. A. Folk, J. D. Watson, G. C. Gardner, and M. J. Manfra

Phys. Rev. B 90, 121405(R) – Published 23 September 2014

Abstract

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.

Received 2 September 2014

DOI:https://doi.org/10.1103/PhysRevB.90.121405

Authors & Affiliations

M. Samani^1,2, A. V. Rossokhaty^1,2, E. Sajadi^1,2, S. Lüscher^1,2, J. A. Folk^1,2,*, J. D. Watson^3,4, G. C. Gardner^4,5, and M. J. Manfra^3,4,5,6

¹Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T1Z4
²Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T1Z4
³Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
⁴Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
⁵School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, USA
⁶School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA

^*jfolk@physics.ubc.ca

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Vol. 90, Iss. 12 — 15 September 2014

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