Homogeneous Linewidth Narrowing of the Charged Exciton via Nuclear Spin Screening in an InAs/GaAs Quantum Dot Ensemble

Abstract

In semiconductor quantum dots, the electron hyperfine interaction with the nuclear spin bath is the leading source of spin decoherence at cryogenic temperature. Using high-resolution two-color differential transmission spectroscopy, we demonstrate that such electron-nuclear coupling also imposes a lower limit for the positively charged exciton dephasing rate, γ, in an ensemble of InAs/GaAs quantum dots. We find that the dephasing rate is sensitive to the strength of the hyperfine interaction, which can be controlled through the application of an external magnetic field in the Faraday configuration. At zero applied field, strong electron-nuclear coupling induces additional dephasing beyond the radiative limit and γ= 230 MHz (0.95 μeV). Screening of the hyperfine interaction is achieved for an external field of ~1 T, resulting in γ= 172 MHz (0.71 μeV) limited only by spontaneous recombination. On the other hand, application of a Voigt magnetic field mixes the spin eigenstates, which increases the dephasing rate by up to 75%. These results are reproduced with a simple and intuitive model that captures the essential features of the electron hyperfine interaction and its influence on γ.

arXiv comment9 pages, 6 figures

References in corpus (20)

• Electron spin relaxation by nuclei in semiconductor quantum dots
• Electron spin decoherence in quantum dots due to interaction with nuclei
• Charge noise and spin noise in a semiconductor quantum device
• Nuclear spin physics in quantum dots: an optical investigation
• Optical pumping of electronic and nuclear spin in single charge-tunable quantum dots
• Voltage-Controlled Optics of a Quantum Dot
• Unconventional motional narrowing in the optical spectrum of a semiconductor quantum dot
• Multidimensional Coherent Photocurrent Spectroscopy of a Semiconductor Nanostructure
• Observation of extremely slow hole spin relaxation in self-assembled quantum dots
• Theory of control of spin/photon interface for quantum networks
• Hole - Nuclear Spin Interaction in Quantum Dots
• Direct measurement of the hole-nuclear spin interaction in single quantum dots
• Coulomb interactions in single, charged self-assembled quantum dots: radiative lifetime and recombination energy
• Fast initialization of the spin state of an electron in a quantum dot in the Voigt configuration
• Two-color spin noise spectroscopy: Using spin fluctuation correlations to reveal homogeneous linewidths within quantum dot ensembles
• Fifth-order nonlinear optical response of excitonic states in an InAs quantum dot ensemble measured with 2D spectroscopy
• Correlation and dephasing effects on the non-radiative coherence between bright excitons in an InAs QD ensemble measured with 2D spectroscopy
• High resolution coherent population trapping on a single hole spin in a semiconductor
• Fast preparation of single hole spin in InAs/GaAs quantum dot in Voigt geometry magnetic field
• Strong Hyperfine-Induced Modulation of an Optically-Driven Hole Spin in an InAs Quantum Dot

Cited by in corpus (3)

• Electronic Coherence Control in a Charged Quantum Dot
• Nonequilibrium spin noise in a quantum dot ensemble
• Optical amplitude and phase modulation dynamics at the single-photon level in a quantum dot ridge waveguide