Npr. Hill et al., ELECTRON-ELECTRON SCATTERING BETWEEN CLOSELY SPACED 2-DIMENSIONAL ELECTRON GASES, Physica. B, Condensed matter, 251, 1998, pp. 868-872
Electron-electron interactions between two closely spaced electron gas
es can be directly measured by the drag voltage induced in one layer w
hen a current is driven through the other. We have used such drag meas
urements of GaAs/AlGaAs double quantum wells to probe both the electro
nic excitations within each layer and the interlayer Coulomb interacti
on. Two contrasting regimes have been explored. First, at high tempera
tures we measure an enhanced drag due to the ''antiscreening'' of the
coupled plasmon modes - a result which is in good agreement with theor
etical predictions. Moreover, we show the importance of many-body corr
ections to the plasmon modes, enabling us to test a local-field descri
ption of the correlations. Second, drag measurements in the quantum Ha
ll regime show more pronounced structure than the Shubnikov-de Haas os
cillations; the drag is more sensitive to spin splitting at high filli
ng factors and enhances the features seen at low filling factors. We s
how that the localised states away from the Landau level centre influe
nce the drag. (C) 1998 Elsevier Science B.V. All rights reserved.