Floating Wigner molecules and possible phase transitions in quantum dots

TL;DR

This paper investigates floating Wigner molecules in quantum dots, demonstrating they have lower energy than fixed crystals and exploring symmetry breaking in arrays due to inter-dot interactions.

Contribution

It introduces the concept of floating Wigner molecules in quantum dots and analyzes their energy advantages and symmetry properties.

Findings

Floating Wigner molecules have lower energy than fixed lattices.

Internal rotational symmetry can be broken in quantum dot arrays.

Degenerate ground states influence symmetry breaking.

Abstract

A floating Wigner crystal differs from the standard one by a spatial averaging over positions of the Wigner-crystal lattice. It has the same internal structure as the fixed crystal, but contrary to it, takes into account rotational and/or translational symmetry of the underlying jellium background. We study properties of a floating Wigner molecule in few-electron spin-polarized quantum dots, and show that the floating solid has the lower energy than the standard Wigner crystal with fixed lattice points. We also argue that internal rotational symmetry of individual dots can be broken in arrays of quantum dots, due to degenerate ground states and inter-dot Coulomb coupling.