Bonding-Antibonding Ground States Transition in Coupled Quantum Dots

The two lowest single-particle hole states in two vertically coupled quntum dots (CQDs) are investigated by using the six-band k • p model. A bonding–antibonding ground-state transition is observed with an increasing interdot distance. This result is counterintuitive since the antibonding molecular ground state is never observed in natural diatomic molecules. By comparing the wavafunction component of hole, the results verify that the reordering of bonding and antibonding orbitals with an increasing interdot distance is caused by spin–orbit interaction of holes.