Local geometry of the Fermi surface and magnetoacoustic response of two-dimensionalelectron systems in strong magnetic fields

Abstract

A semiclassical theory for magnetotransport in a quantum Hall system near filling factorν = 1/2 based on the composite fermion physical picture is used to analyse the effect of localflattening of the composite fermion Fermi surface (CF-FS) upon magnetoacousticoscillations. We report on calculations of the velocity shift and attenuation of a surfaceacoustic wave (SAW) which travels above the two-dimensional electron system, and weshow that local geometry of the CF-FS could give rise to noticeable changes inthe magnitude and phase of the oscillations. We predict these changes will berevealed in experiments, and will be used in further studies of the shape andsymmetries of the CF-FS. The main conclusions reported here could be appliedto analyse magnetotransport in quantum Hall systems at higher filling factorsν = 3/2 and 5/2 for a Fermi-liquid-like state of the system.