Electric-field control of exciton fine structure: atomic scale manipulation of exchange splitting

TL;DR

This paper demonstrates how applying an electric field to symmetric quantum dots can drastically reduce exciton fine structure splitting and reorient exciton polarization, aligning theoretical predictions with experimental observations.

Contribution

It introduces an atomistic tight-binding and configuration interaction approach to explain electric-field induced exciton reorientation and fine structure manipulation in quantum dots.

Findings

Electric field reduces fine structure splitting significantly.

Exciton polarization can be rotated by 90 degrees.

Theoretical results match experimental behaviors.

Abstract

We use atomistic tight-binding theory with a configuration interaction description of Coulomb and exchange effects to describe excitons in symmetric quantum dots in a vertical electric field. We show that field-induced manipulation of exciton orientation and phase produces a drastic reduction of fine structure splitting, an anticrossing, and a 90 degree rotation of polarization, similar to experiment. An atomistic analysis is needed to explain how exciton reorientation modifies anisotropic exchange and fine structure splitting without significantly altering other splittings.