We have investigated the magnetoresistance properties of mesoscopic wires fabricated from a modulation-doped GaAs/(AlGa)As double quantum well structure containing two coupled 2D electron gases (2DEGs). An in-plane magnetic field, B, “tunes” the tunnelling between the 2DEGs and, in a Hall bar device, leads to a resistance feature at B≈10T due to a van Hove singularity in the density of states. In mesoscopic wires this feature becomes a strong resistance peak. We attribute this enhancement to a size effect. In addition, we observe universal conductance fluctuations with the in-plane B. These disappear when B is strong enough to suppress the tunnelling between the wells.
Gompertz, MJ., Ihn, T., main, P., Nogaret, A., Eaves, L., Henini, M., & beaumont, S. (1998). Size-effects and tuning of phase coherence in a double quantum well mesoscopic wire. Physica B: Condensed Matter, 249 - 251, 162-165. https://doi.org/10.1016/S0921-4526(98)00090-8