Impact of a topological defect and Rashba spin-orbit interaction on the thermo-magnetic and optical properties of a 2D semiconductor quantum dot with Gaussian confinement

TL;DR

This study investigates how a topological defect and Rashba spin-orbit interaction influence the thermal and optical properties of a 2D GaAs quantum dot, revealing defect-induced modifications in magnetic behavior and optical transition rules.

Contribution

It introduces a model incorporating a conical disclination and Rashba coupling to analyze their effects on quantum dot properties, providing exact solutions and new insights.

Findings

Peak structure of Schottky anomaly shifts linearly with defect

Defect and Rashba coupling alter paramagnetic transition temperatures

Defect relaxes electronic transition selection rules, enabling new optical resonances

Abstract

In this paper, we examine the effect of introducing a conical disclination on the thermal and optical properties of a two dimensional GaAs quantum dot in the presence of a uniform and constant magnetic field. In particular, our model consists of a single-electron subject to a confining Gaussian potential with a spin-orbit interaction in the Rashba approach. We compute the specific heat and the magnetic susceptibility from the exact solution of the Schr\"odinger equation via the canonical partition function, and it is shown that the peak structure of the Schottky anomaly is linearly displaced as a function of the topological defect. We found that such defect and the Rashba coupling modify the values of the temperature and magnetic field in which the system behaves as a paramagnetic material. Remarkably, the introduction of a conical disclination in the quantum dot relaxes the selection rules for the electronic transitions when an external electromagnetic field is applied. This creates a new set of allowed transitions causing the emergence of semi-suppressed resonances in the absorption coefficient as well as in the refractive index changes which are blue-shifted with respect to the regular transitions for a quantum dot without the defect.