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Experimental Demonstration of Fermi Surface Effects at Filling Factor 5/2

R. L. Willett·K. W. West·L. N. Pfeiffer
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Abstract

Using small wavelength surface acoustic waves (SAW) on ultra-high mobility heterostructures, Fermi surface properties are detected at 5/2 filling factor at temperatures higher than those at which the quantum Hall state forms. An enhanced conductivity is observed at 5/2 by employing sub 0.5 micron wavelength SAW, indicating a quasiparticle mean-free-path substantially smaller than that in the lowest Landau level. These findings are consistent with the presence of a filled Fermi sea of composite fermions, which may pair at lower temperatures to form the 5/2 ground state.

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R. L. Willett, K. W. West, L. N. Pfeiffer. 2001-09-19. Experimental Demonstration of Fermi Surface Effects at Filling Factor 5/2. https://doi.org/10.1103/physrevlett.88.066801

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