Excitations in the Fractional Quantum Hall Effect at ν=1/2: Layered Electron Systems
The fractional quantum Hall effect (FQHE) discovered1 in two-dimensional electron systems subjected to a strong perpendicular magnetic field, has provided us with a unique many-body phenomenon. Recent years have seen quite impressive experimental2,3 and theoretical4–14 developments in this field. Following the seminal work by Laughlin5,6, the ground - state and elementary excitations of an incompressible electron fluid, have been studied by various theoretical techniques. Most of these theoretical works were confined to filling fractions ν (ν=2πl o 2 ρ with l o ≡ (ħc/eB)1/2 being the magnetic length and ρ is the electron density) with odd denominators. The main reason for this choice of filling fractions was because all experiments so far have indicated quite convincingly that FQHE occurs exclusively for odd denominator filling fractions. It is however, very interesting to study the possibilities of observing FQHE at ν=1/2 which is the simplest filling fraction with even denominator.
KeywordsExcitation Spectrum Layer System Collective Excitation Filling Fraction Lower Landau Level
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