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تسجيل مستخدم جديدComposite Fermion Geometric Resonance Near { u} = 1/2 Fractional Quantum Hall State
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We observe geometric resonance features of composite fermions on the flanks of the even denominator { u} = 1/2 fractional quantum Hall state in high-mobility two-dimensional electron and hole systems confined to wide GaAs quantum wells and subjected to a weak, strain-induced, unidirectional periodic potential modulation. The features provide a measure of how close to { u} = 1/2 the system stays single-component and supports a composite fermion Fermi sea before transitioning into a { u} = 1/2 fractional quantum Hall state, presumably the two-component {Psi}331 state.
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Via the application of parallel magnetic field, we induce a single-layer to bilayer transition in two-dimensional electron systems confined to wide GaAs quantum wells, and study the geometric resonance of composite fermions (CFs) with a periodic dens
ity modulation in our samples. The measurements reveal that CFs exist close to bilayer quantum Hall states, formed at Landau level filling factors $ u=1$ and 1/2. Near $ u=1$, the geometric resonance features are consistent with half the total electron density in the bilayer system, implying that CFs prefer to stay in separate layers and exhibit a two-component behavior. In contrast, close to $ u=1/2$, CFs appear single-layer-like (single-component) as their resonance features correspond to the total density.
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