Center for Nanoscience and Fakultät für Physik, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München, Germany.
Phys Rev Lett. 2013 Apr 26;110(17):177602. doi: 10.1103/PhysRevLett.110.177602.
The electron-nuclei (hyperfine) interaction is central to spin qubits in solid state systems. It can be a severe decoherence source but also allows dynamic access to the nuclear spin states. We study a double quantum dot exposed to an on-chip single-domain nanomagnet and show that its inhomogeneous magnetic field crucially modifies the complex nuclear spin dynamics such that the Overhauser field tends to compensate external magnetic fields. This turns out to be beneficial for polarizing the nuclear spin ensemble. We reach a nuclear spin polarization of ≃50%, unrivaled in lateral dots, and explain our manipulation technique using a comprehensive rate equation model.
电子-核（超精细）相互作用是固态系统中自旋量子位的核心。它可以是一个严重的退相干源，但也允许对核自旋态进行动态访问。我们研究了一个暴露在芯片上单畴纳米磁体上的双量子点，并表明其不均匀磁场极大地改变了复杂的核自旋动力学，使得过氧化物场趋于补偿外磁场。这对于极化核自旋集合是有益的。我们达到了 ≃50%的核自旋极化，这在横向点中是无与伦比的，并使用综合速率方程模型解释了我们的操作技术。
