Evidence for universal conductance fluctuations in an open quantum dot under a strictly parallel magnetic field

We investigate the transport properties of semiconductor ballistic cavities subject to a parallel magnetic field. Universal conductance fluctuations are observed on two GaAs/AlGaAs quantum well samples with one and two occupied carrier subbands, respectively. Large differences between the two open quantum dots in both the amplitude and frequency distribution of these fluctuations are analyzed in terms of electron orbital motion and magnetic subband depopulation.