On the origin of the giant SHE in Cu(Bi) alloys

Giant Spin Hall Effect Induced by Skew Scattering from Bismuth Impurities inside Thin Film CuBi Alloys

We demonstrate that a giant spin Hall effect (SHE) can be induced by introducing a small amount of Bi impurities in Cu. Our analysis based on a new 3-dimensional finite element treatment of spin transport shows that the sign of the SHE induced by the Bi impurities is negative and its spin Hall (SH) angle amounts to -0.24. Such a negative large SH angle in CuBi alloys can be explained by applying the resonant scattering model proposed by Fert and Levy [Phys. Rev. Lett. 106, 157208 (2011)] to 6p impurities.

Giant spin Hall effect in half-Heusler alloy topological semimetal YPtBi grown at low temperature

Half-Heusler alloy topological semimetal YPtBi is a promising candidate for an efficient spin source material having both large spin Hall angle $θ$$_{SH}$ and high thermal stability. However, high-quality YPtBi thin films with low bulk carrier density are usually grown at 600$°$C, which exceeds the limitation of 400$°$C for back end of line (BEOL) process. Here, we investigate the crystallinity and spin Hall effect of YPtBi thin films grown at lower growth temperature down to 300$°$C. Although $θ$$_{SH}$ degraded with lowering the growth temperature to 300$°$C due to degradation of the crystal…

Si(111)上具有巨 Rashba 劈裂的 Tl-Pb 单层合金表面圆偏振光生电流效应

Surface Circular Photogalvanic Effect in Tl-Pb Monolayer Alloys on Si(111) with Giant Rashba Splitting

本文发现 Si(111) 上具有巨 Rashba 效应的 Tl-Pb 单层合金可通过圆偏振光生电流效应产生非互易自旋极化光电流，其强度可与更厚的自旋劈裂薄膜相比，证明单原子层材料也能实现光学自旋操控。

Giant Enhancement of Solid Solubility in Monolayer BNC Alloys by Selective Orbital Coupling

Solid solubility (SS) is one of the most important features of alloys, which is usually difficult to be largely tuned in the entire alloy concentrations by external approaches. Some alloys that were supposed to have promising physical properties could turn out to be much less useful because of their poor SS, e.g., the case for monolayer BNC [(BN)1-x(C2)x] alloys. Until now, an effective approach on significantly enhancing SS of (BN)1-x(C2)x in the entire x is still lacking. In this article, a novel mechanism of selective orbital coupling between high energy wrong-bond states and surface states…

Unidirectional Rashba Spin Splitting in Single Layer WS$_{2(1-x)}$Se$_{2x}$ alloy

Atomically thin two-dimensional (2D) layered semiconductors such as transition metal dichalcogenides (TMDs) have attracted considerable attention due to their tunable band gap, intriguing spin-valley physics, piezoelectric effects and potential device applications. Here we study the electronic properties of a single layer WS$_{1.4}$Se$_{0.6}$ alloys. The electronic structure of this alloy, explored using angle resolved photoemission spectroscopy, shows a clear valence band structure anisotropy characterized by two paraboloids shifted in one direction of the k-space by a constant in-plane vecto…

Efficient spin current source using a half-Heusler alloy topological semimetal with Back-End-of-Line compatibility

Topological materials, such as topological insulators (TIs), have great potential for ultralow power spintronic devices, thanks to their giant spin Hall effect. However, the giant spin Hall angle ($θ_{SH}$ > 1) is limited to a few chalcogenide TIs with toxic elements and low melting points, making them challenging for device integration during the silicon Back-End-of-Line (BEOL) process. Here, we show that by using a half-Heusler alloy topological semi-metal (HHA-TSM), YPtBi, it is possible to achieve both a giant $θ_{SH}$ up to 1.6 and a high thermal budget up to 600$°$C. We demonstrate magne…