Surface Acoustic Wave Study of Density-Modulated Phases

Abstract

The existence of density-modulated phases was first inferred from signatures in charge transport experiments (Cooper et al. Phys. Rev. B 60, 285, 1999) [1], (Lilly et al. Phys. Rev. Lett. 82, 394, 1999) [2]. The bubble phase was identified by a reappearance of the integer quantum Hall effect, whereas the stripe phase manifested itself by the anisotropic transport behavior (Sect. 2.5). Since then, research on density-modulated phases has focused primarily on their response to an external current flow. Here, we pursue a different approach and investigate these phases by means of surface acoustic waves. This technique provides an intriguing alternative access to the electron dynamics and conductivity in a two-dimensional electron system.