Electron-drag effects in coupled electron systems

Electron–drag effects in coupled electron systems

The advancement of fabrication and lithography techniques of semiconductors have made it possible to study bi–layer systems made of two electronic layers separated by distances of several hundred Angstroms. In this situation the electrons in layer 1 are distinguishable from those in layer 2, and can communicate through the direct inter–layer Coulomb interaction. In particular, if a current is a...

Linear-response theory of Coulomb drag in coupled electron systems.

Evidence for 2kF electron–electron scattering processes in Coulomb drag

Measurements and calculations of Coulomb drag between two low density, closely spaced, two-dimensional electron systems are reported. The experimentally measured drag exceeds that calculated in the random phase approximation by a significant, and density dependent, factor. Studies of the dependence of the measured drag on the difference in density between the two layers clearly demonstrate that...

Exchange and correlation effects on drag in low density electron bilayers: Coulombandvirtual-optical-phonon-mediated electron-electron interaction

We investigate the effect of exchange and correlation (xc) in low-density electron bilayers. Along with the direct Coulomb interaction, the effective electron-electron interaction mediated by the exchange of virtual polar optical (PO) phonons is considered. We find that the introduction of xc corrections results in a significant enhancement of the transresistivity and qualitative changes in its...

Anomalous coulomb drag in electron-hole bilayers.

We report Coulomb drag measurements on GaAs-AlGaAs electron-hole bilayers. The two layers are separated by a 10 or 25 nm barrier. Below T approximately 1 K we find two features that a Fermi-liquid picture cannot explain. First, the drag on the hole layer shows an upturn, which may be followed by a downturn. Second, the effect is either absent or much weaker in the electron layer, even though th...