手性多肽/铁磁异质结构中分子螺旋度依赖的有效磁场的直接量化

中文摘要 AI 辅助

手性诱导自旋选择性（CISS）指结构手性调控手性体系中自旋输运的现象，在输运实验和光电子发射实验中均已观测到实验特征。除影响输运外，近期实验表明，吸附的手性分子可影响相邻铁磁层的磁状态，提示存在手性诱导效应，但其起源与定量表征仍不明确。本研究在混合分子/铁磁多层膜中探究超越常规直接输运耦合的手性诱导长程磁相互作用，通过绝缘间隔层将吸附手性分子与磁体解耦，证实该相互作用的长程特性；研究显示，具有螺旋结构的手性多肽自组装单分子层可通过对映体依赖的有效磁场作用于铁磁多层膜，该磁场可能由手性声子介导穿过绝缘层产生。利用带有无分子片上参考区域的磁光克尔效应（MOKE）显微镜，通过精确测量局部磁滞回线的可重复偏移，直接量化该有效磁场；提取的有效磁场对相反对映体符号相反，且与对映体过量相关。这些结果为混合异质结构中分子手性与磁响应提供了直接定量关联，建立了可实验获取的CISS相关效应的基准。

英文摘要

Chirality-Induced Spin Selectivity (CISS) refers to structural chirality governing spin transport in chiral systems, with experimental signatures reported in both transport experiments and photoemission. Beyond influencing transport, recent experiments indicate that adsorbed chiral molecules can influence the magnetic state of adjacent ferromagnetic layers, suggesting the existence of chirality-induced effects whose origin and quantitative characterization remain lacking. Here, we investigate chirality-induced long-range magnetic interactions in a hybrid molecular/ferromagnetic multilayer beyond the conventional direct transport coupling. We demonstrate the long-range nature by decoupling the adsorbed chiral molecules from the magnet using an insulating spacer. We show that self-assembled monolayers of chiral polypeptides with a helical structure can act on a ferromagnetic multilayer via an enantiomer-dependent effective magnetic field that may be mediated by chiral phonons through the insulating layer. Using Magneto-Optical Kerr Effect (MOKE) microscopy with on-chip reference regions free of molecules, we directly quantify this field by measuring precisely the reproducible shifts of the local hysteresis loops. The extracted effective field reverses sign for opposite enantiomers and correlates with the enantiomeric excess. These results provide a direct and quantitative link between molecular chirality and magnetic response in hybrid heterostructures, establishing an experimentally accessible benchmark for a CISS-related effect.

发表机构

• Johannes Gutenberg-Universität Mainz（美因茨约翰内斯古腾堡大学）
• Helmholtz Institute Mainz（美因茨亥姆霍兹研究所）
• The Hebrew University of Jerusalem（耶路撒冷希伯来大学）
• GSI Helmholtz-Zentrum für Schwerionenforschung GmbH（德国重离子研究中心亥姆霍兹有限公司）
• University of California, Berkeley（加州大学伯克利分校）
• Uppsala University（乌普萨拉大学）
• Norwegian University of Science and Technology（挪威科技大学）

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