High-efficiency optical pumping of nuclear polarization in a GaAs quantum well

Abstract

The dynamic polarization of nuclear spins by photoexcited electrons is studied in a high quality GaAs/AlGaAs quantum well. We find a surprisingly high efficiency of the spin transfer from the electrons to the nuclei as reflected by a maximum nuclear field of 0.9 T in a tilted external magnetic field of 1 T strength only. This high efficiency is due to a low leakage of spin out of the polarized nuclear system, because mechanisms of spin relaxation other than the hyperfine interaction are strongly suppressed, leading to a long nuclear relaxation time of up to 1000 s. A key ingredient to that end is the low impurity concentration inside the heterostructure, while the electrostatic potential from charged impurities in the surrounding barriers becomes screened through illumination by which the spin relaxation time is increased compared to keeping the system in the dark. This finding indicates a strategy for obtaining high nuclear spin polarization as required for long-lasting carrier spin coherence.

arXiv comment6 pages, 4 figures

References in corpus (9)

• Electron spin decoherence in quantum dots due to interaction with nuclei
• Nuclear Spin Switch in Semiconductor Quantum Dots
• Bistability of the Nuclear Polarisation created through optical pumping in InGaAs Quantum Dots
• Manipulation of the Spin Memory of Electrons in n-GaAs
• Demagnetization of Quantum Dot Nuclear Spins: Breakdown of the Nuclear Spin Temperature Approach
• Efficient dynamical nuclear polarization in quantum dots: Temperature dependence
• Nuclear magnetization in gallium arsenide quantum dots at zero magnetic field
• Nuclear spin relaxation in n-GaAs: from insulating to metallic regime
• Nuclear spin warm-up in bulk n-GaAs

Cited by in corpus (4)

• Single-beam resonant spin amplification of electrons interacting with nuclei in a GaAs/(Al,Ga)As quantum well
• Hyperfine interaction of electrons and holes with nuclei probed by optical orientation in MAPbI${}_3$ perovskite crystals
• Slowly generated anomalously large nuclear field in bulk n-AlGaAs
• Deep optical cooling of coupled nuclear spin-spin and quadrupole reservoirs in a GaAs/(Al,Ga)As quantum well