The Bulk van der Waals Layered Magnet CrSBr is a Quasi-1D Material
The Bulk van der Waals Layered Magnet CrSBr is a Quasi-1D Material
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DOI：
10.1021/acsnano.2c07316
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发表时间：
2023-03-16
期刊：
影响因子：
17.1
通讯作者：
Ross, Frances M.
中科院分区：
文献类型：
--
作者：
Klein, Julian;Pingault, Benjamin;Ross, Frances M.
一维（1D）系统中表现出竞争性电子和磁序的相关量子现象对于研究基本相互作用和激发具有浓厚的兴趣，例如朝永卢廷格液体以及拓扑序和缺陷，其性质与高维对应物中预期的准粒子完全不同。然而，干净的一维电子系统很难通过实验实现，特别是对于磁有序系统。在这里，我们证明了范德华层状磁性半导体 CrSBr 的行为就像嵌入磁有序环境中的准一维材料。强的一维电子特征源自Cr ???S 链以及弱层间杂化和有效质量和介电屏蔽中的各向异性的结合，有效电子质量比为 mXe/mYe ??? 50. 这种极端的各向异性在实验上表现为强电子声子和激子声子相互作用、类佩尔斯结构不稳定性以及来自与金属碳纳米管强度相似的范霍夫奇点的法诺共振。此外，由于维数降低和层间耦合，CrSBr 具有继承一维特征的高结合能和振荡器强度的光谱窄 (1 meV) 激子。总体而言，CrSBr 最好被理解为一堆弱杂化单层，并且似乎是在磁序存在下研究奇异激子和一维相关多体物理的实验上有吸引力的候选者。
Correlated quantum phenomena in one-dimen-sional (1D) systems that exhibit competing electronic and magnetic order are of strong interest for the study of fundamental interactions and excitations, such as Tomonaga???Luttinger liquids and topological orders and defects with properties completely different from the quasiparticles expected in their higher-dimensional counterparts. However, clean 1D electronic systems are difficult to realize experimentally, particularly for magnetically ordered systems. Here, we show that the van der Waals layered magnetic semiconductor CrSBr behaves like a quasi-1D material embedded in a magnetically ordered environment. The strong 1D electronic character originates from the Cr???S chains and the combination of weak interlayer hybridization and anisotropy in effective mass and dielectric screening, with an effective electron mass ratio of mXe/mYe ??? 50. This extreme anisotropy experimentally manifests in strong electron???phonon and exciton???phonon interactions, a Peierls-like structural instability, and a Fano resonance from a van Hove singularity of similar strength to that of metallic carbon nanotubes. Moreover, because of the reduced dimensionality and interlayer coupling, CrSBr hosts spectrally narrow (1 meV) excitons of high binding energy and oscillator strength that inherit the 1D character. Overall, CrSBr is best understood as a stack of weakly hybridized monolayers and appears to be an experimentally attractive candidate for the study of exotic exciton and 1D-correlated many-body physics in the presence of magnetic order.