Anomalous in-plane magneto-optical anisotropy of self-assembled quantum dots

TL;DR

This paper investigates the complex behavior of optical anisotropy in self-assembled quantum dots under in-plane magnetic fields, revealing effects caused by isotropic and anisotropic Zeeman contributions and their compensation.

Contribution

It provides a theoretical framework explaining the anomalous magneto-optical anisotropy in quantum dots, highlighting the roles of isotropic and anisotropic Zeeman effects and their compensation.

Findings

Optical axis can rotate opposite to magnetic field or stay fixed.

Isotropic and anisotropic Zeeman effects influence optical anisotropy.

Built-in uniaxial anisotropy compensates Zeeman effects at B_c = 0.4 T.

Abstract

We report on a complex nontrivial behavior of the optical anisotropy of quantum dots that is induced by a magnetic field in the plane of the sample. We find that the optical axis either rotates in the opposite direction to that of the magnetic field or remains fixed to a given crystalline direction. A theoretical analysis based on the exciton pseudospin Hamiltonian unambiguously demonstrates that these effects are induced by isotropic and anisotropic contributions to the heavy-hole Zeeman term, respectively. The latter is shown to be compensated by a built-in uniaxial anisotropy in a magnetic field B_c = 0.4 T, resulting in an optical response typical for symmetric quantum dots.