Theory of magnetoacoustic transport in modulated quantum Hall systems nearν=1/2

Abstract

Motivated by the experimental results of Willett et al [Phys.Rev. Lett. 78, 4478 (1997)] we develop a magnetotransport theory for the response of a two-dimensional electron gas (2DEG) in the fractional quantum Hall regime near Landau level filling factor ν = 1/2 to the surface acoustic wave (SAW) in the presence of an added periodic density modulation. We assume there exists a composite fermion Fermi surface (CF-FS) at ν = 1/2, and we show that the deformation of the circular CF-FS due to the density modulation can be at the origin of the observed transport anomalies for the experimental conditions. Our analysis is carried out particularly for the nonlocal case which corresponds to the SAW experiments. We introduce a new model of a deformed CF-FS. The model permits us to explain anomalous features of the response of the modulated 2DEG to the SAW near ν = 1/2 : namely, the nonlinear wave vector dependence of the electron conductivity, the appearance of peaks in the SAW velocity shift and attenuation and the anisotropy of the effect, all of which originate from contributions to the conductivity tensor due to the regions of the CF-FS, which are flattened by the applied modulation.

Local geometry of the Fermi surface and quantum oscillations in the linear response of metals

“…Likewise, the flattening points at the FS may give rise to some anomalies in the magnetoacoustic response of a two-dimensional electron gas, as shown in the papers [9,10].…”

Magnetic Translations for a Spatially Periodic Magnetic Field

“…Some recent experiments have shown that variation of density in two-dimensional electron systems lead to a fictitious periodic magnetic field [5] and a geometric resonance of the classical cyclotron orbit and the field period. A theory of this effect has been lately proposed Zimbovskaya and Birman [6].…”

Fermi-liquid effects in transresistivity in quantum Hall double layers near ν=1/2

“…To get a suitable approximation for the CF conductivity we start from the standard solution of the Boltzmann transport equation for the CF distribution function. This gives us the following results for the CF conductivity components for a single layer [9]:…”