Exciton spin decay modified by strong electron-hole exchange interaction

TL;DR

This paper investigates how strong electron-hole exchange interactions influence exciton spin decay, revealing a dominant mechanism that restricts electron spin precession, supported by experimental Hanle effect measurements and theoretical modeling.

Contribution

It introduces a new understanding of exciton spin decay mechanisms under strong exchange interaction, supported by combined experimental and theoretical analysis.

Findings

Electron spin precession is confined within a sector defined by magnetic and exchange fields.

The dominant decay mechanism is identified through Hanle effect measurements.

Theoretical calculations align with experimental results, confirming the proposed model.

Abstract

We study exciton spin decay in the regime of strong electron-hole exchange interaction. In this regime the electron spin precession is restricted within a sector formed by the external magnetic field and the effective exchange fields triggered by random spin flips of the hole. Using Hanle effect measurements, we demonstrate that this mechanism dominates our experiments in CdTe/(Cd,Mg)Te quantum wells. The calculations provide a consistent description of the experimental results, which is supported by independent measurements of the parameters entering the model.