Re-entrant pinning of Wigner molecules in a magnetic field due to a Coulomb impurity

TL;DR

This paper investigates how Coulomb impurities influence the pinning and orientation of Wigner molecules in quantum dots under magnetic fields, revealing re-entrant pinning behavior and differences based on impurity charge.

Contribution

It presents the first exact diagonalization study of impurity effects on Wigner molecule pinning and orientation in magnetic fields.

Findings

Re-entrant pinning of Wigner molecules as a function of magnetic field.

Magnetic field induced re-orientation of Wigner molecules.

Different pinning behaviors with positive and negative Coulomb impurities.

Abstract

Pinning of magnetic-field induced Wigner molecules (WMs) confined in parabolic two-dimensional quantum dots by a charged defect is studied by an exact diagonalization approach. We found a re-entrant pinning of the WMs as function of the magnetic field, a magnetic field induced re-orientation of the WMs and a qualitatively different pinning behaviour in the presence of a positive and negative Coulomb impurity.