Frictional Drag between Two Dilute Two-Dimensional Hole Layers

Abstract

We report drag measurements on dilute double layer two-dimensional hole systems in the regime of ${r}_{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}19--39$. We observed a strong enhancement of the drag over the simple Boltzmann calculations of Coulomb interaction, and deviations from the ${T}^{2}$ dependence which cannot be explained by phonon-mediated, plasmon-enhanced, or disorder-related processes. We suggest that this deviation results from interaction effects in the dilute regime.