Density imbalance effect on the Coulomb drag upturn in an undoped electron-hole bilayer

摘要: A low-temperature upturn of the Coulomb drag resistivity measured in an undoped electron-hole bilayer (uEHBL) device, possibly manifesting from exciton formation or condensation, was recently observed. The effects density imbalance on this are examined. Measurements as a function temperature uEHBL with 20-nm-wide ${\text{Al}}_{0.90}{\text{Ga}}_{0.10}\text{As}$ barrier layer at various imbalances presented. results show increasing either two-dimensional system reduced, both within and above regime stronger dependence than weak-coupling theory predicts. comparison data numerical calculations presence pairing fluctuations, which qualitatively reproduce behavior, is also predict peak matched densities, not reflected by measurements.