Probing Single-Electron Spin Decoherence in Quantum Dots using Charged Excitons

TL;DR

This paper introduces a method using optical detection of magnetic resonance to measure the decoherence time of a single electron spin in quantum dots, enabling insights into spin coherence properties via optical signals.

Contribution

It proposes a novel ODMR-based technique for measuring electron spin decoherence in quantum dots, utilizing circularly polarized lasers and ESR fields.

Findings

Demonstrates how ESR linewidth relates to spin decoherence

Shows modulation of photoluminescence correlates with spin flips

Analyzes cw and pulsed laser schemes for ODMR

Abstract

We propose to use optical detection of magnetic resonance (ODMR) to measure the decoherence time T_{2} of a single electron spin in a semiconductor quantum dot. The electron is in one of the spin 1/2 states and a circularly polarized laser can only create an optical excitation for one of the electron spin states due to Pauli blocking. An applied electron spin resonance (ESR) field leads to Rabi spin flips and thus to a modulation of the photoluminescence or, alternatively, of the photocurrent. This allows one to measure the ESR linewidth and the coherent Rabi oscillations, from which the electron spin decoherence can be determined. We study different possible schemes for such an ODMR setup, including cw or pulsed laser excitation.