利用电子自旋进行信息处理是半导体自旋电子学的主要目标之一。最近发现的铁电Rashba半导体（FERSCs）中自旋的电性和非易失性控制有望将存储、存储和计算功能结合起来，这些新材料的激发性质来自自旋自由度耦合到电极化的独特性质，从而极轴本质上打破了反演对称性（IS）。另一方面，这类材料所需的大自旋-轨道耦合（SOC）也会产生电荷-自旋相互转换现象，如自旋霍尔效应（SHE）。最近对高对称性顺电体进行的实验研究表明其具有强的自旋霍尔效应，但是其来源仍然不清楚。
来自美国杜克大学大学的Jagoda Sławińska和北德克萨斯大学的Jagoda Sławińska的团队，基于密度泛函理论（DFT）的计算，定量地估计两种材料的低对称和高对称结构的自旋霍尔电导（SHCs）。发现铁电相确实可以增强SHE，而不是顺电结构。并从自旋Berry曲率的附加贡献来解释这个效应，它起源于极性相的自旋分裂电子态。其次，由于半导体中SHE的实现需要掺杂，研究了极性畸变随载流子浓度的演化，并估计了维持低对称相的掺杂临界水平。通过对这些材料中驱动铁电性的孤对载流子的分析，发现GeTe中的极性位移可以维持在 1021/cm3以上的临界空穴浓度，而SnTe中的微小畸变在最低掺杂水平下消失。最后，计算了掺杂结构的自旋霍尔角，证明了自旋霍尔效应确实可以在极性相位中实现。自旋霍尔效应、Rashba自旋织构和铁电共存于一种材料中，将有助于设计新型的无磁性ELD的一体化自旋电子器件。在实际实现SHE和Rashba效应（RE）电控制等应用方面具有广阔的前景。
该文近期发表于npj Computational Materials 6: 7 (2020)，英文标题与摘要如下，点击https://www.nature.com/articles/s41524-020-0274-0可以自由获取论文PDF。
Spin Hall effect in prototype Rashba ferroelectrics GeTe and SnTe
Haihang Wang, Priya Gopal , Silvia Picozzi, Stefano Curtarolo , Marco Buongiorno Nardelli and Jagoda Sławińska
Ferroelectric Rashba semiconductors (FERSCs) have recently emerged as a promising class of spintronics materials. The peculiar coupling between spin and polar degrees of freedom responsible for several exceptional properties, including ferroelectric switching of Rashba spin texture, suggests that the electron’s spin could be controlled by using only electric fields. In this regard, recent experimental studies revealing charge-to-spin interconversion phenomena in two prototypical FERSCs, GeTe and SnTe, appear extremely relevant. Here, by employing density functional theory calculations, we investigate spin Hall effect (SHE) in these materials and show that it can be large either in ferroelectric or paraelectric structure. We further explore the compatibility between doping required for the practical realization of SHE in semiconductors and polar distortions which determine Rashba-related phenomena in FERSCs, but which could be suppressed by free charge carriers. Based on the analysis of the lone pairs which drive ferroelectricity in these materials, we have found that the polar displacements in GeTe can be sustained up to a critical hole concentration of over ~1021/cm3, while the tiny distortions in SnTe vanish at a minimal level of doping. Finally, we have estimated spin Hall angles for doped structures and demonstrated that the spin Hall effect could be indeed achieved in a polar phase. We believe that the confirmation of spin Hall effect, Rashba spin textures and ferroelectricity coexisting in one material will be helpful for design of novel all-in-one spintronics devices operating without magnetic fields.