Enhancement of nuclear spin coherence times by driving dynamic nuclear polarization at defect centers in solids
Enhancement of nuclear spin coherence times by driving dynamic nuclear polarization at defect centers in solids
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DOI：
10.1103/physrevb.99.205423
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发表时间：
2018-10
影响因子：
3.7
通讯作者：
Gargee Sharma;T. Gaebel;E. Rej;D. Reilly;S. Economou;Edwin Barnes
中科院分区：
文献类型：
--
作者：
Gargee Sharma;T. Gaebel;E. Rej;D. Reilly;S. Economou;Edwin Barnes
核自旋的超极化可以使强大的成像和传感技术成为可能，只要这种超极化的寿命足够长。最近对纳米金刚石$^{13}$C核自旋的实验表明，通过在缺陷中心驱动电子-核触发器过程来建立动态核极化（DNP），可以将弛豫时间延长三个数量级。这一发现提出了核自旋相干时间是否也受到超极化过程的影响的问题。在这里，我们从理论上考察了DNP作为超极化驱动时间的函数对核自旋相干时间的影响。为此，我们开发了一种微观理论，在固体中与微波驱动缺陷中心耦合的核自旋系综中，受核间偶极相互作用介导的自旋扩散的影响。我们发现，与弛豫时间类似，核自旋相干时间可以根据驱动时间大幅度增加几个数量级。我们的理论模型和结果将有助于当前和未来通过DNP提高核自旋相干时间的实验。
The hyperpolarization of nuclear spins can enable powerful imaging and sensing techniques provided the hyperpolarization is sufficiently long-lived. Recent experiments on nanodiamond $^{13}$C nuclear spins demonstrate that relaxation times can be extended by three orders of magnitude by building up dynamic nuclear polarization (DNP) through the driving of electron-nuclear flip-flop processes at defect centers. This finding raises the question of whether the nuclear spin coherence times are also impacted by this hyperpolarization process. Here, we theoretically examine the effect of DNP on the nuclear spin coherence times as a function of the hyperpolarization drive time. We do this by developing a microscopic theory of DNP in a nuclear spin ensemble coupled to microwave-driven defect centers in solids and subject to spin diffusion mediated by internuclear dipolar interactions. We find that, similarly to relaxation times, the nuclear spin coherence times can be increased substantially by a few orders of magnitude depending on the driving time. Our theoretical model and results will be useful for current and future experiments on enhancing nuclear spin coherence times via DNP.