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arXiv · 1204.4759

Experimental evidence of low-lying gapped excitations in the quantum fluid at nu=5/2

U. Wurstbauer·K. W. West·L. N. Pfeiffer·A. Pinczuk
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Abstract

The low-lying neutral excitation spectrum of the incompressible quantum Hall fluid at $ν=5/2$ is investigated by inelastic light scattering. Gapped modes are observable only in a very narrow filling factor range centered at 5/2 at energies that overlap estimates from transport activation gaps. The modes are interpreted as critical points in the wave-vector dispersion of excitations that preserve spin orientation. For very small changes $|δν|\lesssim 0.01$ the gapped modes disappear and a continuum of low-lying excitations takes over indicating the transition from an incompressible fluid at 5/2 to a compressible state. Observations of spin wave modes indicate spin polarization of the 5/2 and 2+1/3 quantum Hall fluids.

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U. Wurstbauer, K. W. West, L. N. Pfeiffer, A. Pinczuk. 2012-04-20. Experimental evidence of low-lying gapped excitations in the quantum fluid at nu=5/2. https://arxiv.org/abs/1204.4759

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