García-Blázquez M A, Dednam W, Palacios J J
Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
Department of Physics, Science Campus, University of South Africa, Florida Park, Johannesburg 1710, South Africa.
J Phys Chem Lett. 2023 Sep 7;14(35):7931-7939. doi: 10.1021/acs.jpclett.3c01922. Epub 2023 Aug 30.
It is generally accepted that spin-dependent electron transmission may appear in chiral systems, even without magnetic components, as long as significant spin-orbit coupling is present in some of its elements. However, how this chirality-induced spin selectivity (CISS) manifests in experiments, where the system is taken out of equilibrium, is still debated. Aided by group theoretical considerations and nonequilibrium DFT-based quantum transport calculations, here we show that when spatial symmetries that forbid a finite spin polarization in equilibrium are broken, a spin accumulation appears at finite bias in an arbitrary two-terminal nanojunction. Furthermore, when a suitably magnetized detector is introduced into the system, the net spin accumulation, in turn, translates into a finite magneto-conductance. The symmetry prerequisites are mostly analogous to those for the spin polarization at any bias with the vectorial nature given by the direction of magnetization, hence establishing an interconnection between these quantities.
人们普遍认为,只要手性系统的某些元素中存在显著的自旋轨道耦合,即使没有磁性成分,自旋相关的电子传输也可能出现。然而,在实验中,当系统处于非平衡状态时,这种手性诱导的自旋选择性(CISS)是如何表现的,仍然存在争议。借助群论考虑和基于非平衡密度泛函理论的量子输运计算,我们在此表明,当禁止平衡态下有限自旋极化的空间对称性被打破时,在任意的两端纳米结中,有限偏压下会出现自旋积累。此外,当将一个适当磁化的探测器引入系统时,净自旋积累反过来会转化为有限的磁电导。对称前提大多类似于任何偏压下自旋极化的前提,其矢量性质由磁化方向给出,从而在这些量之间建立了一种联系。