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arXiv · 0801.3312

Intrinsic Gap of the nu=5/2 Fractional Quantum Hall State

C. R. Dean·B. A. Piot·P. Hayden·S. Das Sarma·G. Gervais·L. N. Pfeiffer·K. W. West
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Abstract

The fractional quantum Hall effect is observed at low field, in a regime where the cyclotron energy is smaller than the Coulomb interaction. The nu=5/2 excitation gap is measured to be 262+/-15 mK at ~2.6 T, in good agreement with previous measurements performed on samples with similar mobility, but with electronic density larger by a factor of two. The role of disorder on the nu=5/2 gap is examined. Comparison between experiment and theory indicates that a large discrepancy remains for the intrinsic gap extrapolated from the infinite mobility (zero disorder) limit. In contrast, no such large discrepancy is found for the nu=1/3 Laughlin state. The observation of the nu=5/2 state in the low-field regime implies that inclusion of non-perturbative Landau level mixing may be necessary to better understand the energetics of half-filled fractional quantum hall liquids.

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C. R. Dean, B. A. Piot, P. Hayden, S. Das Sarma, G. Gervais, L. N. Pfeiffer, K. W. West. 2008-01-30. Intrinsic Gap of the nu=5/2 Fractional Quantum Hall State. https://doi.org/10.1103/physrevlett.100.146803

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