Anomalous magnetophotoluminescence as a result of level repulsion in arrays of quantum dots

TL;DR

This study investigates anomalous magnetophotoluminescence in quantum dot arrays, revealing level repulsion effects under magnetic fields and providing a theoretical model that aligns well with experimental data.

Contribution

It introduces a theory explaining anomalous SPL sensitivity due to level repulsion in quantum dots, supported by experimental validation and correlation analysis.

Findings

Anomalous magnetic field sensitivity observed in SPL spectra.

Level repulsion explains the anomalous effects.

Estimated correlation in excited level positions is 94%.

Abstract

Selectively excited photoluminescence (SPL) of an array of self-organized In$_{0.5}$Ga$_{0.5}$As quantum dots has been measured in a magnetic field up to 11T. Anomalous magnetic field sensitivity of the SPL spectra has been observed under conditions for which the regular photoluminescence spectra is insensitive to the magnetic field due to large inhomogeneous broadening. The anomalous sensitivity is interpreted in terms of the repulsion of excited levels of the dots in a random potential. A theory presented to describe this phenomena is in excellent agreement with the experimental data. The data estimated the correlation in the positions of excited levels of the dots to be 94%. The magnetic field dependence allows the determination of the reduced cyclotron effective mass in a dot. For our sample we have obtained $m_em_h/(m_e+m_h)=0.034m_0$.