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valley of (In,Al)As/AlAs quantum dots
摘要： The electron-nuclei hyperfine interaction of electrons in indirect band gap (In,Al)As/AlAs quantum dots with type-I band alignment has been experimentally studied by measuring the polarization degree of the photoluminescence in a transverse magnetic field (Hanle effect) and the polarization recovery in a longitudinal magnetic field. The different symmetries of the X valley electron Bloch amplitudes at the As, In, and Al nuclei strongly affect the hyperfine interaction. The hyperfine constants corresponding to these nuclei have been determined.
关键词： X valley,hyperfine constants,Bloch amplitudes,Hanle effect,polarization recovery,photoluminescence,quantum dots,electron-nuclei hyperfine interaction
更新于2025-09-23 15:21:01
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Strong polarization of individual nuclear spins weakly coupled to nitrogen-vacancy color centers in diamond
摘要： We experimentally demonstrate high degree of polarization of 13C nuclear spins weakly interacting with nitrogen-vacancy (NV) centers in diamond. We combine coherent microwave excitation pulses with optical illumination to provide controlled relaxation and achieve a polarity-tunable, fast nuclear polarization of degree higher than 85% at room temperature for remote 13C nuclear spins exhibiting hyperfine interaction strength with NV centers of the order of 600 kHz. We show with the aid of numerical simulation that the anisotropic hyperfine tensor components naturally provide a route to control spin mixing parameter so that highly efficient nuclear polarization is enabled through careful tuning of nuclear quantization axis by external magnetic field. We further discuss spin dynamics and wide applicability of this method to various target 13C nuclear spins around the NV center electron spin. The proposed control method demonstrates an efficient and versatile route to realize, for example, high-fidelity spin register initialization and quantum metrology using nuclear spin resources in solids.
关键词： nitrogen-vacancy (NV),nitrogen-vacancy center,spin initialization,hyperfine interaction,spin polarization
更新于2025-09-23 15:19:57
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A silicon quantum-dot-coupled nuclear spin qubit
摘要： Single nuclear spins in the solid state are a potential future platform for quantum computing, because they possess long coherence times and offer excellent controllability. Measurements can be performed via localized electrons, such as those in single atom dopants or crystal defects. However, establishing long-range interactions between multiple dopants or defects is challenging. Conversely, in lithographically defined quantum dots, tunable interdot electron tunnelling allows direct coupling of electron spin-based qubits in neighbouring dots. Moreover, the compatibility with semiconductor fabrication techniques may allow for scaling to large numbers of qubits in the future. Unfortunately, hyperfine interactions are typically too weak to address single nuclei. Here we show that for electrons in silicon metal–oxide–semiconductor quantum dots the hyperfine interaction is sufficient to initialize, read out and control single 29Si nuclear spins. This approach combines the long coherence times of nuclear spins with the flexibility and scalability of quantum dot systems. We demonstrate high-fidelity projective readout and control of the nuclear spin qubit, as well as entanglement between the nuclear and electron spins. Crucially, we find that both the nuclear spin and electron spin retain their coherence while moving the electron between quantum dots. Hence we envision long-range nuclear–nuclear entanglement via electron shuttling. Our results establish nuclear spins in quantum dots as a powerful new resource for quantum processing.
关键词： entanglement,hyperfine interaction,nuclear spins,quantum dots,silicon,coherence times,quantum computing
更新于2025-09-12 10:27:22
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Influence of a Longitudinal Field on the Large In‐Plane Nuclear Field Formation in Single Quantum Dots
摘要： In single self-assembled InAlAs quantum dots, the role of nuclear quadrupole interaction in the in-plane nuclear field formation was studied by the Hanle effect measurements. The origin of nuclear quadrupole interaction and the influence of a longitudinal magnetic field were revealed. The results indicated the multirole of the nuclear quadrupole interaction in the in-plane nuclear field formation.
关键词： hyperfine interaction,nuclear quadrupole interaction,quantum dot
更新于2025-09-11 14:15:04