Fractional Quantum Hall Effect in Silicon MOSFETs

Abstract

In Si MOSPET structures with high mobility of 2D electrons in a strong perpendicular magnetic field (H ≤ 20 T) the thermoactivated conductivity is used for determination of activation gaps W in the energy spectrum of interacting electrons at the fractional filling factors: ν=1/3, 2/3, 4/3, 7/3 and 4/5. These gaps increase proportionally to the reciprocal magnetic length under the condition that the electron mobility μ_e is fixed. The dependence of the activation gaps on H and μ_e can be factorized within a simple relation. A destruction of PQHE due to disorder is discussed. The magnitudes found for W, and their dependence on H and μ_e, correlate with the theoretical conception concerning the condensation of 2D electrons into quantum incompressible Fermi fluid. An optical spectroscopy method for the determination of the gaps for quasi-particle excitations in the Fermi fluid energy spectrum is suggested.