Floating Wigner molecules and possible phase transitions in quantum dots

摘要

A floating Wigner crystal differs from the standard one by a spatialaveraging over positions of the Wigner-crystal lattice. It has the sameinternal structure as the fixed crystal, but contrary to it, takes into accountrotational and/or translational symmetry of the underlying jellium background.We study properties of a floating Wigner molecule in few-electronspin-polarized quantum dots, and show that the floating solid has the lowerenergy than the standard Wigner crystal with fixed lattice points. We alsoargue that internal rotational symmetry of individual dots can be broken inarrays of quantum dots, due to degenerate ground states and inter-dot Coulombcoupling.