Zhang Shunhong, Zhou Yi, Liu Feng, Liu Zheng
Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
Sci Bull (Beijing). 2019 Nov 15;64(21):1584-1591. doi: 10.1016/j.scib.2019.08.028. Epub 2019 Aug 28.
The discovery of ideal spin-1/2 kagome antiferromagnets Herbertsmithite and Zn-doped Barlowite represents a breakthrough in the quest for quantum spin liquids (QSLs), and nuclear magnetic resonance (NMR) spectroscopy plays a prominent role in revealing the quantum paramagnetism in these compounds. However, interpretation of NMR data that is often masked by defects can be controversial. Here, we show that the most significant interaction strength for NMR, i.e. the hyperfine coupling (HFC) strength, can be reasonably reproduced by first-principles calculations for these proposed QSLs. Applying this method to a supercell containing Cu-Zn defects enables us to map out the variation and distribution of HFC at different nuclear sites. This predictive power is expected to bridge the missing link in the analysis of the low-temperature NMR data.
理想的自旋1/2 Kagome反铁磁体赫伯史密斯石和锌掺杂巴洛石的发现代表了在寻找量子自旋液体（QSL）方面的一项突破，并且核磁共振（NMR）光谱在揭示这些化合物中的量子顺磁性方面发挥着重要作用。然而，对经常被缺陷掩盖的NMR数据的解释可能存在争议。在这里，我们表明，对于这些提出的QSL，通过第一性原理计算可以合理地再现NMR最重要的相互作用强度，即超精细耦合（HFC）强度。将这种方法应用于包含铜 - 锌缺陷的超晶胞，使我们能够描绘出不同核位点处HFC的变化和分布。这种预测能力有望弥合低温NMR数据分析中缺失的环节。
