Investigation of Spin Pairing in a Semiconductor Quantum Dot

Abstract

Semiconductor quantum dots have been patterned into a Ga[Al]As heterostructure by local oxidation of the GaAs cap layer with an Atomic Force Microscope. The combination of high electron density and reduced shape deformation allows us to observe spin pairs in the dot's energy level spectrum, which is demonstrated via correlated parametric evolution of the Coulomb blockade resonances in perpendicular magnetic fields. Here, we investigate the systematic change of the spacing between correlated Coulomb peaks as the magnetic field is increased. Furthermore we look at the distribution of even and odd nearest neighbor level separations and find a clear difference between the respective statistics.