Composite Fermions in Modulated Structures: Transport and Surface Acoustic Waves

TL;DR

This paper uses semiclassical composite-fermion theory to analyze how weak periodic density modulations significantly affect surface-acoustic-wave propagation in quantum Hall systems near filling factor 1/2, explaining experimental results.

Contribution

It demonstrates the impact of density modulation on SAW propagation and predicts similar effects in dc transport measurements, advancing understanding of composite fermions in modulated structures.

Findings

Weak density modulation dramatically alters SAW propagation.

Proposes explanation for experimental SAW features.

Predicts similar structures in dc transport measurements.

Abstract

Motivated by a recent experiment of Willett et al. [Phys. Rev. Lett. 78, 4478 (1997)], we employ semiclassical composite-fermion theory to study the effect of a periodic density modulation on a quantum Hall system near Landau level filling factor nu=1/2. We show that even a weak density modulation leads to dramatic changes in surface-acoustic-wave (SAW) propagation, and propose an explanation for several key features of the experimental observations. We predict that properly arranged dc transport measurements would show a structure similar to that seen in SAW measurements.