Non-reciprocal Coulomb drag in a ballistic quantum wire

1D Coulomb drag serves as a platform for probing electron-electron interactions in 1D systems. Device with ballistic wire conductance allows us to study Coulomb drag with minimal disorder effects in the drag wire. Surprisingly, a non-reciprocal signal is still detected in our ballistic device, though the reciprocal components dominate over a much wider regime compared to devices with non-ballistic wires. The regime of reciprocal dominance coincides with the gate voltages where shoulders or plateaus appear in conductance. We speculate that the non-reciprocal contribution arises from the impact of low energy disorder in the system, as the ballistic conductance is significantly suppressed in the low-bias regime, while approaching ideal quantized value again under high temperature and/or high bias voltage. The temperature dependence of the non-reciprocal signal follows a power law with an exponent aligning with a diffusion model despite the drag wire being ballistic.