Optical Aharonov-Bohm Effect on Wigner Molecules in Type-II Semiconductor Quantum Dots

TL;DR

This paper theoretically investigates the optical Aharonov-Bohm effect on Wigner molecules formed by strongly correlated electrons in type-II semiconductor quantum dots, revealing unique oscillation patterns and optical signatures.

Contribution

It demonstrates the formation of Wigner molecules in quantum dots and predicts their distinct optical and magnetic oscillation behaviors, providing new insights into many-body quantum effects.

Findings

Electron correlations lead to Wigner molecule formation.

Energy oscillates with magnetic field at half the period of single electrons.

Optical signatures show discontinuous changes at ground state transitions.

Abstract

We theoretically examine the magnetoluminescence from a trion and a biexciton in a type-II semiconductor quantum dot, in which holes are confined inside the quantum dot and electrons are in a ring-shaped region surrounding the quantum dot. First, we show that two electrons in the trion and biexciton are strongly correlated to each other, forming a Wigner molecule: Since the relative motion of electrons is frozen, they behave as a composite particle whose mass and charge are twice those of a single electron. As a result, the energy of the trion and biexciton oscillates as a function of magnetic field with half the period of the single-electron Aharonov-Bohm oscillation. Next, we evaluate the photoluminescence. Both the peak position and peak height change discontinuously at the transition of the many-body ground state, implying a possible observation of the Wigner molecule by the optical experiment.