Dynamic Nuclear Spin Polarization of Liquids and Gases in Contact with Nanostructured Diamond
Dynamic Nuclear Spin Polarization of Liquids and Gases in Contact with Nanostructured Diamond
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DOI：
10.1021/nl500147b
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发表时间：
2014-05-01
期刊：
影响因子：
10.8
通讯作者：
Meriles, Carlos A.
中科院分区：
文献类型：
--
作者：
Abrams, Daniel;Trusheim, Matthew E.;Meriles, Carlos A.
自旋极化的光泵浦可以产生几乎完全的自旋有序，但其应用仅限于选择原子气体和凝聚态系统。在这里，我们从理论上研究了一种新的路线，在任意流体中，目标分子暴露于位于主机材料表面附近的极化顺磁中心的核自旋超极化。我们发现，吸附的核自旋弛豫到正或负极化取决于平均顺磁中心深度和纳米级表面拓扑结构。对于特定的情况下，在金刚石中的光泵氮空位中心，我们计算强核自旋极化在中等磁场提供的晶体表面工程表面粗糙度在几个纳米的范围内。平衡核自旋温度仅弱依赖于描述分子吸附动力学的相关时间，并且在其他非极化顺磁中心的存在下是稳健的。这些功能可以被利用来阻止流动的液体或气体，因为我们说明了数值的流体与光泵金刚石纳米结构接触的模型情况。
Optical pumping of spin polarization can produce almost complete spin order but its application is restricted to select atomic gases and condensed matter systems. Here, we theoretically investigate a novel route to nuclear spin hyperpolarization in arbitrary fluids in which target molecules are exposed to polarized paramagnetic centers located near the surface of a host material. We find that adsorbed nuclear spins relax to positive or negative polarization depending on the average paramagnetic center depth and nanoscale surface topology. For the particular case of optically pumped nitrogen-vacancy centers in diamond, we calculate strong nuclear spin polarization at moderate magnetic fields provided the crystal surface is engineered with surface roughness in the few-nanometer range. The equilibrium nuclear spin temperature depends only weakly on the correlation time describing the molecular adsorption dynamics and is robust in the presence of other, unpolarized paramagnetic centers. These features could be exploited to polarize flowing liquids or gases, as we illustrate numerically for the model case of a fluid brought in contact with an optically pumped diamond nanostructure.