Experimental Studies Into Chiral Induced Spin Selectivity

在这个由化学部化学结构、动态和机制B项目资助的项目中，匹兹堡大学化学系的David H. Waldeck教授将探索在非常薄的材料薄膜（金属氧化物或多肽）下，电子的磁偶极子是如何按照速度方向排列的。这项研究的目的是了解分子的螺旋结构如何影响电子磁矩的方向，并检查这些特征是否可以纳入薄金属氧化物薄膜中，以产生具有自旋磁矩首选方向的电子电流。电子磁矩的排列及其在电路中的操作可能对新型信息存储设备的设计和创造具有重要意义。本项目处于材料化学与物理化学的交叉领域，适合对各级科学家进行教育。通过科学工具包借阅图书馆向匹兹堡地区学校（初中和高中）开展的外展活动也将是资助项目的一部分。与一个德国小组和一个以色列小组的合作将为学生研究人员提供有益的国际经验。最近的实验（和理论）表明，当电子穿过手性分子（或结构）时，它们会产生一个有效的磁场，使电子的磁矩与传播方向一致。本实验旨在阐明手性薄膜的结构特征如何影响自旋取向的程度。在这项工作的一个重点中，将检查螺旋分子的单层厚膜，以了解自旋排列如何受到螺旋结构（螺距，长度等）的影响。在这项工作的第二个重点中，重点是研究超薄金属氧化物手性薄膜传输电子的自旋排列如何取决于金属氧化物能带位置和薄膜厚度。后一项研究可能对新型电子器件的设计具有重要意义，例如自旋扭矩存储器。这些研究旨在确定需要纳入的重要特征，以实现手性诱导自旋选择性效应的定量精确理论模型。

In this project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor David H. Waldeck of the Department of Chemistry at the University Pittsburgh will explore how electrons have their magnetic dipoles aligned with respect to the direction of their velocity by very thin films of material (either metal oxides or polypeptides). The goal of this research is to understand how the helical structure of molecules affects the direction of an electron's magnetic moment and to examine whether those characteristics can be incorporated in thin metal oxide films for creating electron currents that have a preferred direction for the spin magnetic moments. The alignment of electron magnetic moments and their manipulation in circuits could have important implications for the design and creation of new types of information memory devices. The project lies at the interface of materials chemistry and physical chemistry, and it is well suited to the education of scientists at all levels. Outreach activities to Pittsburgh area schools (middle school and high school) through a Science Kit Lending Library will also be part of the funded project. The collaboration with a German group and an Israeli group will provide a beneficial international experience for the student researchers. Recent experiments (and theory) show that as electrons move through a chiral molecule (or structure) they generate an effective magnetic field which acts to align the electrons' magnetic moment to the propagation direction. The proposed experimental studies aim to elucidate how structural features of chiral thin films affect the degree of spin alignment. In one thrust of the work, monolayer thick films of helical molecules will be examined to see how the spin alignment is affected by the helix structure (pitch, length, etc.). In a second thrust of the work, the focus is on how the spin alignment for electrons transmitted by ultrathin chiral films of metal oxides depends on the metal oxides energy band location and the film's thickness. These latter studies could have important implications for the design of new electronic devices, such as spin-torque memories. These studies are designed to identify the important features that will need to be incorporated to achieve a quantitatively accurate theoretical model of the chiral induced spin selectivity effect.