论文标题
手性诱导自旋选择性的异常自旋极化
Unusual Spin Polarization in the Chirality Induced Spin Selectivity
论文作者
论文摘要
手性诱导的自旋选择性（CISS）是指电子在纳米级设备中通过有机手性分子后旋转极化的事实。在CISS中，通常认为手性分子是一种自旋滤波器，一个偏爱的自旋传输，相反的自旋得到了反射，即传输和反射的电子表现出相反的自旋极化。在这项工作中，我们指出，这种自旋滤波器方案与平衡旋转电流必须消失的原理相矛盾。取而代之的是，我们发现传输和反射的电子呈现相同类型的自旋极化，这实际上对于两端设备而言是无处不在的。更准确地说，手性分子扮演自旋偏振剂而不是自旋滤波器的作用。自旋极化的方向取决于分子手性和电子入射方向。自旋极化的大小在设备中的局部自旋轨道耦合上回复。我们的工作对CISS有了更深入的了解，并解释了最近的实验，例如CISS驱动的异常效果。
Chirality-induced spin selectivity (CISS) refers to the fact that electrons get spin polarized after passing through organic chiral molecules in a nanoscale device. In CISS, chiral molecules are commonly believed to be a spin filter through which one favored spin transmits and the opposite spin gets reflected, i.e., transmitted and reflected electrons exhibit opposite spin polarization. In this work, we point out that such a spin filter scenario contradicts the principle that equilibrium spin current must vanish. Instead, we find that both transmitted and reflected electrons present the same type spin polarization, which is actually ubiquitous for a two-terminal device. More accurately, chiral molecules play the role of a spin polarizer rather than a spin filter. The direction of spin polarization is determined by the molecule chirality and the electron incident direction. And the magnitude of spin polarization replies on local spin-orbit coupling in the device. Our work brings a deeper understanding on CISS and interprets recent experiments, for example, the CISS-driven anomalous Hall effect.
