Role of Interactions in Electronic Structure of a Two-Electron Quantum Dot Molecule

We have studied a two-electron quantum dot molecule in a magnetic field. The electron interaction is treated accurately by the direct diagonalization of the Hamiltonian matrix. We calculate two lowest energy levels of the two-electron quantum dot molecule in a magnetic field. Our results show that the electron interactions are significant, as they can change the total spin of the two-electron ground state of the system by adjusting the magnetic field between S=0 and S=1. The energy difference ΔE between the lowest S=0 and S=1 states is shown as a function of the axial magnetic field. We found that the energy difference between the lowest S=0 and S=1 states in the strong-B S=0 state varies linearly. Our results provide a possible realization for a qubit to be fabricated by current growth techniques.