Linear-response theory of Coulomb drag in coupled electron systems

Linear-response theory of Coulomb drag 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...

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...

Theory of Coulomb drag in graphene

We study the Coulomb drag between two single graphene sheets in intrinsic and extrinsic graphene systems with no interlayer tunneling. The general expression for the nonlinear susceptibility appropriate for single-layer graphene systems is derived using the diagrammatic perturbation theory, and the corresponding exact zerotemperature expression is obtained analytically. We find that, despite th...

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...