Topological Weyl Semimetals for Spintronic Devices

拓扑Weyl半金属（WSM）在费米能量附近的动量空间中携带着巨大的Berry曲率，因为它的传导带和价带线性地穿过作为Berry曲率奇点（源/汇）的节点。考虑到WSM中的大Berry曲率和强自旋-轨道耦合，我们提出WSM可以表现出强的本征自旋霍尔效应（SHE），这是自旋依赖的Berry相的一种表现。SHE可用于在自旋电子器件中产生或检测自旋电流。特别是，这些自旋电流可以用来激发或操纵磁性纳米元件和畴壁。我们建议对WSM TaP和最近发现的相关化合物的SHE进行理论和实验研究。我们将使用蒸发和溅射两种不同的沉积技术制备并优化高质量WSM薄膜的生长。自旋电子器件将由这些WSM薄膜耦合到各种磁性薄膜，由我们的从头计算的见解指导。我们提出的SHE器件将为拓扑材料的室温应用铺平道路。此外，我们将为其他SPP合作者提供WSM薄膜样品和单晶。

The topological Weyl semimetal (WSM) carries giant Berry curvatures in the momentum space near the Fermi energy, because its conduction and valence bands cross linearly through nodes that are singularity points (source/sink) of the Berry curvature. Considering the large Berry curvatures and strong spin-orbit coupling in a WSM, we propose that a WSM can exhibit a strong intrinsic spin Hall effect (SHE), which is a manifestation of the spin-dependent Berry phase. The SHE can be used to electrically generate or detect spin currents in spintronic devices. These spin currents can, in particular, be used to excite or manipulate magnetic nano-elements and domain walls. We propose to perform both theoretical and experimental investigations of the SHE of the WSM TaP and related compounds that have been discovered recently. We will fabricate and optimize the growth of high quality WSM thin films using two different deposition techniques, evaporation and sputtering. Spintronic devices will be formed from these WSM films by coupling them to various magnetic thin films, guided by the insights of our ab-initio calculations. Our proposed SHE devices will pave the way to room-temperature applications of topological materials. In addition, we will offer WSM thin film samples and single crystals for other SPP collaborators.