Spin-orbit effects on two-electron states in nanowhisker double quantum dots

We investigate theoretically the combined effects of the electron-electron and the Rashba spin-orbit interactions on two electrons confined in quasi-one-dimensional AlInSb-based double quantum dots. We calculate the two-electron wave functions and explore the interplay between these two interactions on the energy levels and the spin of the states. The energy spectrum as a function of an applied magnetic field shows crossings and anticrossings between triplet and singlet states, associated with level mixing induced by the spin-orbit coupling. We find that the fields at which these crossings occur can be naturally controlled by the interdot barrier width, which controls the exchange integral in the structure.