Coulomb Drag by Small Momentum Transfer between Quantum Wires

We demonstrate that in a wide range of temperatures Coulomb drag between two weakly coupled quantum wires is dominated by processes with a small interwire momentum transfer. Such processes, not accounted for in the conventional Luttinger liquid theory, cause drag only because the electron dispersion relation is not linear. The corresponding contribution to the drag resistance scales with temperature as $T^2$ if the wires are identical, and as $T^5$ if the wires are different.

Figure 1

Coulomb drag between quantum wires. A dc current $I_1$ flows through the active wire (1). A voltage bias $V_2$ is applied to the passive wire (2) in such a way that $I_2=0$.

Figure 2

Sketch of the temperature dependence of the drag resistivity between identical wires. The small momentum transfer contribution considered in this Letter dominates at $T>T^{*}$; the ratio $T^{*}/{ϵ}_F$ is exponentially small for $k_{F}d>1$.