Tunable contributions from momentum-transfer and rectification to 1D Coulomb drag.

We report 1D Coulomb Drag measurements in both laterally and vertically coupled GaAs/AlGaAs quantum wires. The drag resistance R_D exhibits the standard modulation as the wires’s subband occupancy is varied. The drag signal show non-monotonic temperature dependence for both lateral and vertical wires, suggesting strong electron-electron interactions. The lateral wires have a barrier width of ~150 nm, while the vertical wires have a barrier width of ~15 nm. The drag signal between the lateral wires notably breaks the broken Onsager relation and shows non-linear I-V characteristics suggesting a drag signal predominantly dominated by charge rectification. However, in vertically-coupled quantum wires, rectifying drag signal breaking Onsager relations are mainly observed at large 1D subband occupancies while momentum-transfer induced drag signal is dominant in the single 1D subband regime. The transition between both regimes is studied both as a function of temperature and of drive current.