van der Waals Heterostructures Based on Nanolayered Paramagnetic Tm(II) Compounds and Boron Nitride for Investigating Spin Frustration
van der Waals Heterostructures Based on Nanolayered Paramagnetic Tm(II) Compounds and Boron Nitride for Investigating Spin Frustration
复制标题
基于纳米层顺磁 Tm(II) 化合物和氮化硼的范德华异质结构用于研究自旋挫败
DOI：
10.1021/acsanm.3c00662
复制
发表时间：
2023
影响因子：
5.9
通讯作者：
Evans, William J.
中科院分区：
文献类型：
--
作者：
Moore, William N.;McSorley, Timothy J.;Vincent, Alexandre;Ziller, Joseph W.;Jauregui, Luis A.;Evans, William J.
通过研究层状Tm（II）化合物[（THF）Cs（μ-η5：η5-Cp′）3 TmII]n（Cp′ = C5 H4 SiMe 3），探索了分子前体在制备用于构建货车德瓦耳斯异质结构的薄膜组分中的应用.该化合物由金属铯还原Cp′ 3 TmIII而成，晶体结构为六方网状结构，由Tm（II）离子和Cs（I）离子交替排列，并由Cp′配体桥接而成。该化合物的完整表征，包括SQUID磁力测定法，与4f 13 Tm（II）一致。虽然S = 1/2 Tm（II）离子在层状结构中的三角形取向表明了自旋挫折的潜在环境，但SQUID数据表明这些金属中心缺乏足够的相互作用来执行这种行为。在手套箱中，在低温下成功剥离空气和水分敏感的单晶，以产生薄膜。这些可以堆叠在六方氮化硼下以产生空气稳定的货车德瓦尔斯异质结构，其允许通过AFM分析以确定覆盖的含Tm结构的约50层的厚度。
The utility of molecular precursors to create thin-film components for constructing van der Waals heterostructures was explored by studying the layered Tm(II) compound [(THF)Cs(μ-η5:η5-Cp′)3TmII]n(Cp′ = C5H4SiMe3). This compound, synthesized by the reduction of Cp′3TmIIIwith metallic cesium, crystallizes as layers of hexagonal nets composed of Tm(II) ions and Cs(I) ions at alternating vertices, bridged by Cp′ ligands. Full characterization of the compound, including SQUID magnetometry, was consistent with 4f13Tm(II). Though the triangular orientation ofS= 1/2 Tm(II) ions in the layered structure indicated a potential environment for spin frustration, the SQUID data suggest these metal centers lack enough interaction to enforce such behavior. Successful exfoliation of the air- and moisture-sensitive single crystals was achieved in a glovebox at low temperatures to yield thin films. These could be stacked under hexagonal boron nitride to create an air-stable van der Waals heterostructure, which allowed analysis by AFM to determine a thickness of approximately 50 layers for the covered Tm-containing structure.