Single-electron energy levels of a parallel double-quantum dot

Abstract

We have calculated the non-interacting single-particle energy spectrum of a parabolic parallel double-quantum dot in a magnetic field. The magic numbers change according to the distance between dots. We find that, due to coupling between two dots, rotational symmetry is lifted, and electrons form charge density puddles even without interaction. A crossover from coupled to separate dots occurs as the magnetic field is increased. This feature is consistent with experimental observations.