2013/09/05 by G. Sallen, Gregory Sallen, S. Kunz +13
Mathematics · Physics and Astronomy · #Condensed matter physics #Field (mathematics) #Gallium arsenide #Magnetic field #Magnetization #Mathematics #Physics #Quantum and electron transport phenomena #Quantum dot #Quantum mechanics #Semiconductor Quantum Structures and Devices #Topological Materials and Phenomena #Zero (linguistics) #cond-mat.mes-hall
paper · pdf · doi:10.1038/ncomms4268
published as Nature Communications 5, Article number: 3268 (2014) open · 8 pages, 3 figures
arxiv created 2013/09/05 · openalex publication_date 2014/02/06 · arxiv updated 2014/09/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Optical and electrical control of the nuclear spin system allows enhancing the sensitivity of NMR applications and spin-based information storage and processing. Dynamic nuclear polarization in semiconductors is commonly achieved in the presence of a stabilizing external magnetic field. Here we report efficient optical pumping of nuclear spins at zero magnetic field in strain-free GaAs quantum dots. The strong interaction of a single, optically injected electron spin with the nuclear spins acts as a stabilizing, effective magnetic field (Knight field) on the nuclei. We optically tune the Knight field amplitude and direction. In combination with a small transverse magnetic field, we are able to control the longitudinal and transverse components of the nuclear spin polarization in the absence of lattice strain—that is, in dots with strongly reduced static nuclear quadrupole effects, as reproduced by our model calculations. Optical control of nuclear spin polarization in semiconductor quantum dots is promising for applications in NMR imaging. Sallen et al.report efficient dynamic nuclear polarization at zero magnetic field in strain-free gallium arsenide quantum dots with Knight fields dominating the nuclear quadrupole effects.