ABSTRACT
This chapter investigates the influence of impurities and dangling bonds on the conductance anomalies in GaAs quantum point contacts (QPCs) created by side gates, in the presence of lateral spin–orbit coupling (LSOC). It considers the effects of attractive and repulsive scatterers in the narrow portion of the QPC and dangling bonds on its side walls. In QPC experiments, the charge state of an impurity is often affected by sample handling, such as temperature cycling, when the sample is brought back to room temperature between low temperature measurements. Using an nonequilibrium Green's function analysis of a small model QPC, three ingredients were found to be essential for generating a strong spin polarization: an asymmetric lateral confinement, an LSOC induced by the lateral confining potential of the QPC, and a strong electron–electron interaction.
