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arXiv · 1109.1491

Evolution of the 7/2 fractional quantum Hall state in two-subband systems

Yang Liu·J. Shabani·D. Kamburov·M. Shayegan·L. N. Pfeiffer·K. W. West·K. W. Baldwin
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Abstract

We report the evolution of the fractional quantum Hall state (FQHS) at even-denominator filling factor $ν=7/2$ in wide GaAs quantum wells in which electrons occupy two electric subbands. The data reveal subtle and distinct evolutions as a function of density, magnetic field tilt-angle, or symmetry of the charge distribution. When the charge distribution is strongly asymmetric, there is a remarkable persistence of a resistance minimum near $ν=7/2$ when two Landau levels belonging to the two subbands cross at the Fermi energy. The field position of this minimum tracks the 5/2 filling of the symmetric subband, suggesting a pinning of the crossing levels and a developing 5/2 FQHS in the symmetric subband even when the antisymmetric level is partially filled.

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Yang Liu, J. Shabani, D. Kamburov, M. Shayegan, L. N. Pfeiffer, K. W. West, K. W. Baldwin. 2011-09-07. Evolution of the 7/2 fractional quantum Hall state in two-subband systems. https://doi.org/10.1103/physrevlett.107.266802

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