Orbital effect, subband depopulation, and conductance fluctuations in ballistic quantum dots under a tilted magnetic field

Using two-dimensional electron gases (2DEGs) confined to wide and narrow quantum wells, we study the magnetoconductance of ballistic quantum dots as a function of the well width and the tilt angle of the magnetic field B with respect to the 2DEG. Both the wide and narrow quantum well dots feature magnetoconductance fluctuations (MCFs) at intermediate tilt angles, due to the finite thickness of the electron layer and the field-induced orbital effect. As B approaches a strictly parallel configuration, a saturation of the MCFs' spectral distribution is observed, combined with the persistence of a limited number of frequency components in the case of the narrow quantum well dot. It is found that the onset of saturation strongly depends on the width of the confining well. Using the results of self-consistent Poisson-Schrödinger simulations, the magnetoconductance is rescaled as a function of the Fermi level in the 2DEG. We perform a power spectrum analysis of the parallel field-induced MCFs in the energy space and find a good agreement with theoretical predictions.