Jia Lei, Wang Chenchen, Zhang Yuchun, Yang Liu, Yan Yong
CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China.
School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710126, China.
ACS Nano. 2020 Jun 23;14(6):6607-6615. doi: 10.1021/acsnano.9b07681. Epub 2020 May 20.
Chiral materials, natural or synthetic, have been widely studied since Pasteur's separation of enantiomers over a century ago. The connection between electron transmission and chirality was, however, established recently where one spin was preferably selected by the chiral molecules, displaying a typical chirality-induced spin selectivity (CISS) effect. Currently, this CISS effect was mainly demonstrated in the molecular-scale devices. Herein, we explored this effect in a microscale device where an efficient spin selectivity was found in the self-assembled superhelical conducting polyaniline (PANI) microfibers. A spin-selective efficiency up to 80% (not magnetoresistance) was achieved when spins traversed the . 2-6 μm-long helical channels at room temperature. Importantly, the long-range ordering of chiral PANI molecules is crucial to observe this efficient spin selectivity, whereas no selective transmission was found in the "amorphous" chiral PANIs. This efficient spin selectivity was subsequently rationalized by using an extended Su-Schrieffer-Heeger model where the Rashba spin-orbit coupling was considered. We expect these results could inspire the research of organic spintronics by using molecularly ordered, self-assembled, and chiral π-conjugated materials.
自一个多世纪前巴斯德分离对映体以来，天然或合成的手性材料就得到了广泛研究。然而，电子传输与手性之间的联系是最近才建立起来的，其中手性分子优先选择一种自旋，表现出典型的手性诱导自旋选择性（CISS）效应。目前，这种CISS效应主要在分子尺度的器件中得到证明。在此，我们在一个微米尺度的器件中探索了这种效应，在自组装的超螺旋导电聚苯胺（PANI）微纤维中发现了有效的自旋选择性。当自旋在室温下穿过2 - 6μm长的螺旋通道时，实现了高达80%的自旋选择性效率（非磁阻）。重要的是，手性PANI分子的长程有序对于观察这种有效的自旋选择性至关重要，而在“无定形”手性PANI中未发现选择性传输。随后，通过使用考虑了Rashba自旋轨道耦合的扩展Su - Schrieffer - Heeger模型，对这种有效的自旋选择性进行了合理解释。我们期望这些结果能够激发利用分子有序、自组装和手性π共轭材料开展有机自旋电子学的研究。
