Magneto-Coulomb oscillations

We examine the low-temperature magnetotransport properties of a lateral semiconductor quantum dot defined electrostatically on a GaAs-${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As two-dimensional electron-gas (2DEG) heterostructure. We depopulate the point contacts to form tunnel barriers, at a series of fixed gate biases, by varying the magnetic field. With both dot and ungated 2DEG in the ν=2 filling-factor regime we observe periodic oscillations in the magnetoresistance resulting from single-electron magnetodepopulation of the dot. We substantiate the Coulombic nature of this characteristic, which is peculiar to high magnetic fields and relatively large (∼2 μm diameter) dots, by developing a theory for Coulomb-blockade-regulated magnetoconductance oscillations. Based on our theory, and on self-consistent calculations of our device classical capacitances and potential profile, we predict an oscillation period which is in reasonable agreement with the observations.