Photoluminescence rings in Corbino disk at quantizing magnetic fields

TL;DR

This study investigates the formation of concentric photoluminescence rings in a Corbino disk under strong magnetic fields, revealing internal stripe structures in a 2DEG that are independent of external currents.

Contribution

It provides the first spatially resolved observation of photoluminescence rings in a Corbino disk, linking them to stripe formations in a 2DEG under quantizing magnetic fields.

Findings

Concentric rings travel across the sample with changing magnetic field.

The structure's topology excludes external current influence.

Rings are attributed to compressible and incompressible stripes in 2DEG.

Abstract

Spatially resolved photoluminescence of modulation doped AlGaAs/GaAs heterojunction was investigated in a sample of Corbino disk geometry subject to strong perpendicular magnetic fields. Significant spatial modulation of the photoluminescence was observed in form of one or more concentric rings which travelled across the sample when the magnetic field strength was varied. A topology of the observed structure excludes the possibility of being a trace of an external current. The effect is attributed to formation of compressible and incompressible stripes in a 2DEG density gradient across the sample.