Abstract：Chirality-induced spin selectivity (CISS) is an effect in which structural chirality engenders spin polarization in the electrical current from a nonmagnetic electrode. This phenomenon has profound fundamental implications on the intricate interplay between structural chirality, electron motion, and spin polarization. The spin-valve effect and the Hanle effect are two main electrical approaches to study spin transport in molecular junctions.

We fabricated junctions of (Ga, Mn)As/alpha-helix L-polyalanines (AHPA-L)/Au and measured the junction magnetoconductance at cryogenic temperatures to quantitatively analyze the spin-valve effect. The experiment provided definitive evidence for both linear and nonlinear response components. We further resolved the fundamental mechanism how chiral geometry influences the electronic spin, by unambiguously identifying the origin of necessary spin-orbit coupling (SOC). In junctions of GaAs/AHPA-L/Au, the Hanle effect exhibit universal temperature and bias current dependences. Our experimental work suggests a new scheme of spintronics free of any magnetic materials based on the CISS effect.

主讲人简介：柳天寒博士2014年本科毕业于厦门大学物理学系。2021年获美国佛罗里达州立大学(FSU)凝聚态物理博士学位，师从熊鹏教授。现在美国加州大学洛杉矶分校(UCLA)从事博士后研究，师从Paul S. Weiss教授。主要研究方向为自旋输运、半导体自旋电子学器件以及手性结构诱导自旋选择性(chirality-induced spin selectivity, CISS)，以第一/通讯作者身份在Nature Communications, ACS Nano等期刊上发表多篇学术论文。