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We present evidence supporting the weakly paired Moore-Read phase in the half-filled second Landau level, focusing on some of the qualitative features of its excitations. Based on numerical studies, we study both neutral excitations and skyrmions. We show that systems with odd particle number at the flux Nφ=2N-3 can be interpreted as a neutral fermion mode of one unpaired fermion, which is gapped. The energetics of neutral fermions interacting with pairs of quasiparticles is found to be in agreement with predictions for non-abelian statistics of the Ising type with degenerate fusion channels 1 and ψ [1]. Skyrmions are found to be present at low enough fields, and are promoted by disorder [2]. In particular, we discuss signatures of the ν=5/2 Hall liquid in photoluminescence (PL) experiments [3]: The neutral fermion mode is found to have two distinct minima, resulting in a double-peak structure in the PL spectrum [1]. On the other hand, a valence hole in proximity to the 2DEG induces a disorder potential that locally favours skyrmions, thus mimicking an unpolarized environment.
[1] G. Möller, A. Wójs, N. R. Cooper, arXiv:1009.4956. [2] A. Wójs, G. Möller, S. H. Simon, and N. R. Cooper, Phys. Rev. Lett. 104, 086801 (2010). [3] Stern et al., Phys. Rev. Lett. 105, 096801 (2010). |
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