Zheng Haining, Ghosh Arup, Swamynadhan M J, Wang Gang, Zhang Qihan, Wu Xiao, Abdelwahab Ibrahim, Wong Walter P D, Xu Qing-Hua, Ghosh Saurabh, Chen Jingsheng, Campbell Branton J, Stroppa Alessandro, Lin Junhao, Mahendiran Ramanathan, Loh Kian Ping
Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China.
Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore.
J Am Chem Soc. 2023 Aug 23;145(33):18549-18559. doi: 10.1021/jacs.3c05503. Epub 2023 Aug 14.
Organic-inorganic metal hybrids with their tailorable lattice dimensionality and intrinsic spin-splitting properties are interesting material platforms for spintronic applications. While the spin decoherence process is extensively studied in lead- and tin-based hybrids, these systems generally show short spin decoherence lifetimes, and their correlation with the lattice framework is still not well-understood. Herein, we synthesized magnetic manganese hybrid single crystals of (4-fluorobenzylamine)MnCl, (()-3-fluoropyrrolidinium)MnCl, and (pyrrolidinium)MnCl, which represent a change in lattice dimensionality from 2D and 1D to 0D, and studied their spin decoherence processes using continuous-wave electron spin resonance spectroscopy. All manganese hybrids exhibit nanosecond-scale spin decoherence time τ dominated by the symmetry-directed spin exchange interaction strengths of Mn-Mn pairs, which is much longer than lead- and tin-based metal hybrids. In contrast to the similar temperature variation laws of τ in 2D and 0D structures, which first increase and gradually drop afterward, the 1D structure presents a monotonous rise of τ with the temperatures, indicating the strong correlation of spin decoherence with the lattice rigidity of the inorganic framework. This is also rationalized on the basis that the spin decoherence is governed by the competitive contributions from motional narrowing (prolonging the τ) and electron-phonon coupling interaction (shortening the τ), both of which are thermally activated, with the difference that the former is more pronounced in rigid crystalline lattices.
具有可定制晶格维度和固有自旋分裂特性的有机-无机金属杂化物是自旋电子学应用中有趣的材料平台。虽然在铅基和锡基杂化物中对自旋退相干过程进行了广泛研究，但这些体系通常显示出自旋退相干寿命较短，并且它们与晶格框架的相关性仍未得到很好的理解。在此，我们合成了(4-氟苄胺)MnCl、(±)-3-氟吡咯烷鎓)MnCl和(吡咯烷鎓)MnCl的磁性锰杂化单晶，它们代表了从二维、一维到零维的晶格维度变化，并使用连续波电子自旋共振光谱研究了它们的自旋退相干过程。所有锰杂化物都表现出由Mn-Mn对的对称定向自旋交换相互作用强度主导的纳秒级自旋退相干时间τ，这比铅基和锡基金属杂化物长得多。与二维和零维结构中τ的类似温度变化规律（先增加然后逐渐下降）不同，一维结构中τ随温度单调上升，表明自旋退相干与无机框架的晶格刚性有很强的相关性。这也基于自旋退相干由运动变窄（延长τ）和电子-声子耦合相互作用（缩短τ）的竞争贡献所控制这一事实得到合理解释，这两者都是热激活的，不同之处在于前者在刚性晶格中更为明显。
