Spin Inertia of Resident and Photoexcited Carriers in Singly-Charged Quantum Dots

TL;DR

This paper investigates spin dynamics in singly-charged (In,Ga)As/GaAs quantum dots using the spin inertia effect, revealing how spin polarization depends on magnetic field and excitation conditions, and distinguishing mechanisms for resident carriers.

Contribution

It introduces a method to analyze spin dynamics in quantum dots via spin inertia, identifying distinct behaviors for n- and p-type dots and providing parameters for ground and excited states.

Findings

Spin polarization shows V- and M-like dependence on magnetic field for n- and p-type QDs.

Different microscopic mechanisms govern spin orientation in resident carriers.

Parameters of spin dynamics are determined for both ground and excited states.

Abstract

The spin dynamics in a broad range of systems can be studied using circularly polarized optical excitation with alternating helicity. The dependence of spin polarization on the frequency of helicity alternation, known as the spin inertia effect, is used here to study the spin dynamics in singly-charged (In,Ga)As/GaAs quantum dots (QDs) providing insight into spin generation and accumulation processes. We demonstrate that the dependence of spin polarization in $n$- and $p$-type QDs on the external magnetic field has a characteristic V- and M-like shape, respectively. This difference is related to different microscopic mechanisms of resident carriers spin orientation. It allows us to determine the parameters of the spin dynamics both for the ground and excited states of singly-charged QDs.