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arXiv 2408.09436cond-mat.mtrl-sci
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硅碳中室温下地球磁场中的核自旋极化

Nuclear spin polarization in silicon carbide at room temperature in the Earth's magnetic field

Helmholtz-Zentrum Dresden-Rossendorf(亥姆霍兹德累斯顿-罗斯多夫中心);ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology(ICFO光子科学研究所,巴塞罗那科技研究院)

A. N. Anisimov, A. V. Poshakinskiy, G. V. Astakhov

AI总结:

在地球磁场下,利用光学激发和射频驱动实现SiC中核自旋的高效极化,为室温核自旋控制及量子逻辑门应用提供新方法。

摘要:

耦合的电子-核自旋代表一个有前途的量子系统,其中通过超精细相互作用,光诱导的电子自旋极化可以动态地转移到核自旋上。大多数动态核极化(DNP)实验是在低温或中等外部磁场下进行的,后者对磁场方向非常敏感。在这里,我们证明了在地球磁场下,SiC中的29Si核自旋可以在室温下高效极化。我们利用光学检测磁共振(ODMR)线的不对称分裂,这种分裂固有于半整数S=3/2电子自旋,使得涉及29Si核的特定跃迁可以被无线电波(RF)场清晰分离并选择性地驱动。作为模型系统,我们使用6H-SiC中的V3硅空位,其零场分裂参数与超精细相互作用常数相当。我们的理论模型考虑了在光学激发下结合RF驱动的DNP,并与实验数据非常吻合。在高保真度电子自旋极化的情况下,所提出的DNP协议导致核自旋的超深度光学冷却,有效温度约为50nK。这些结果提供了一种在常温条件下控制核自旋的简便方法,代表了实现核超极化用于磁共振成像和长核自旋记忆用于量子逻辑门的重要一步。

英文摘要:

Coupled electron-nuclear spins represent a promising quantum system, where the optically induced electron spin polarization can be dynamically transferred to nuclear spins via the hyperfine interaction. Most experiments on dynamic nuclear polarization (DNP) are performed at cryogenic temperatures and/or in moderate external magnetic fields, the latter approach being very sensitive to the magnetic field orientation. Here, we demonstrate that the $^{29}$Si nuclear spins in SiC can be efficiently polarized at room temperature even in the Earth's magnetic field. We exploit the asymmetric splitting of the optically detected magnetic resonance (ODMR) lines inherent to half-integer $S = 3/2$ electron spins, such that the certain transitions involving $^{29}$Si nuclei can be clearly separated and selectively addressed using radiofrequency (RF) fields. As a model system, we use the V3 silicon vacancy in 6H-SiC, which has the zero-filed splitting parameter comparable with the hyperfine interaction constant. Our theoretical model considers DNP under optical excitation in combination with RF driving and agrees very well with the experimental data. In the case of high-fidelity electron spin polarization, the proposed DNP protocol leads to ultra-deep optical cooling of nuclear spins with an effective temperature of about 50 nK. These results provide a straightforward approach for controlling the nuclear spin under ambient conditions, representing an important step toward realizing nuclear hyperpolarization for magnetic resonance imaging and long nuclear spin memory for quantum logic gates.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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