Bhowmick Deb Kumar, Das Tapan Kumar, Santra Kakali, Mondal Amit Kumar, Tassinari Francesco, Schwarz Rony, Diesendruck Charles E, Naaman Ron
Department of Chemical and Biological Physics, Weizmann Institute, Rehovot 7610001, Israel.
Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy.
Sci Adv. 2022 Aug 12;8(32):eabq2727. doi: 10.1126/sciadv.abq2727. Epub 2022 Aug 10.
We describe the spin polarization-induced chirogenic electropolymerization of achiral 2-vinylpyridine, which forms a layer of enantioenhanced isotactic polymer on the electrode. The product formed is enantioenriched in asymmetric carbon polymer. To confirm the chirality of the polymer film formed on the electrode, we also measured its electron spin polarization properties as a function of its thickness. Two methods were used: First, spin polarization was measured by applying magnetic contact atomic force microscopy, and second, magnetoresistance was assessed in a sandwich-like four-point contact structure. We observed high spin-selective electron transmission, even for a layer thickness of 120 nm. A correlation exists between the change in the circular dichroism signal and the change in the spin polarization, as a function of thickness. The spin-filtering efficiency increases with temperature.
我们描述了非手性的2-乙烯基吡啶的自旋极化诱导的手性电聚合反应，该反应在电极上形成了一层对映体增强的等规聚合物。形成的产物在不对称碳聚合物中是对映体富集的。为了确认在电极上形成的聚合物膜的手性，我们还测量了其电子自旋极化性质随膜厚度的变化。使用了两种方法：第一，通过应用磁接触原子力显微镜测量自旋极化；第二，在三明治状四点接触结构中评估磁电阻。即使对于120nm的层厚度，我们也观察到了高自旋选择性电子传输。作为厚度的函数，圆二色性信号的变化与自旋极化的变化之间存在相关性。自旋过滤效率随温度升高而增加。
