Effect of Chiral Molecules on the Electron's Spin Wavefunction at Interfaces
Effect of Chiral Molecules on the Electron's Spin Wavefunction at Interfaces
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DOI：
10.1021/acs.jpclett.9b03487
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发表时间：
2020-02-20
影响因子：
5.7
通讯作者：
Waldeck, David H.
中科院分区：
文献类型：
--
作者：
Ghosh, Supriya;Mishra, Suryakant;Waldeck, David H.
在手性分子自组装单分子膜覆盖的铁磁性薄膜电极上的开尔文探针测量表明，电子从金属电极向手性分子的穿透取决于铁磁体的磁化方向和分子的手性。观察到了高达100 mV的静电电位差。这些变化源于外加的振荡电场，它驱动自旋相关的电荷从铁磁衬底渗透到手性分子。研究了反应的对映专一性与磁化强度、磁化方向、手性和手性长度的函数关系。根据手征诱导的自旋选择性(CISS)效应，这些新现象是合理的，在这种效应中，来自铁磁的一个自旋取向的电子比另一个取向的电子更容易穿透到手性分子中。这里显示的大的电势变化(室温下的>；KT)表明，这一现象对于手性自旋电子器件中的自旋输运和手性分子的磁电化学是重要的。
Kelvin-probe measurements on ferromagnetic thin film electrodes coated with self-assembled monolayers of chiral molecules reveal that the electron penetration from the metal electrode into the chiral molecules depends on the ferromagnet's magnetization direction and the molecules' chirality. Electrostatic potential differences as large as 100 mV are observed. These changes arise from the applied oscillating electric field, which drives spin-dependent charge penetration from the ferromagnetic substrate to the chiral molecules. The enantiospecificity of the response is studied as a function of the magnetization strength, the magnetization direction, and the handedness and length of the chiral molecules. These new phenomena are rationalized in terms of the chiral-induced spin selectivity (CISS) effect, in which one spin orientation of electrons from the ferromagnet penetrates more easily into a chiral molecule than does the other orientation. The large potential changes (>kT at room temperature) manifested here imply that this phenomenon is important for spin transport in chiral spintronic devices and for magneto-electrochemistry of chiral molecules.