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Universality and Phase Diagram around Half-filled Landau Level

L. W. Wong·H. W. Jiang·W. J. Schaff
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Abstract

Gated GaAs/AlGaAs heterostructures were used to determine the low-temperature behavior of the two-dimensional electron gas near filling factor nu=1/2 in the disorder-magnetic-field plane. We identify a line on which sigma_{xy} is temperature independent, has value sigma_{xy}=0.5 (e^{2}/h), and a distinct line on which rho_{xy}=2 (h/e^{2}). The phase boundaries between the Hall insulator and the principal quantum Hall liquids at nu=1 and 1/3 show levitation of the delocalized states of the first Landau levels for electrons and composite fermions. Finally, the data suggest that there is no true metallic phase around nu=1/2.

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L. W. Wong, H. W. Jiang, W. J. Schaff. 1997-01-15. Universality and Phase Diagram around Half-filled Landau Level. https://doi.org/10.1103/physrevb.54.r17323

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