Deformed molecular states of quantum dots in strong magnetic fields

The effect of a shearing electric field on molecular states of electrons in quantum dots in strong magnetic fields is investigated theoretically. The electron density in circularly symmetric dots is circularly symmetric but the pair correlation function has peaks whose positions have the same symmetry as the classical energy minimum. For small numbers of electrons this is analogous to a rotating ring of electrons. The shearing electric field breaks the circular symmetry and stretches the ring, leading to states with linear symmetry. This transition is found to have a strong effect on the addition energy of a dot and can be either sudden or continuous, depending on the value of the magnetic field. It may be possible to use this effect as an experimental probe of the physical nature of dot states. (C) 2001 Elsevier Science B.V. All rights reserved.