Direct observation of spin-layer locking by local Rashba effect in monolayer semiconducting PtSe(2) film.
Direct observation of spin-layer locking by local Rashba effect in monolayer semiconducting PtSe(2) film.
复制标题
单层半导体 PtSe2 薄膜中局域 Rashba 效应直接观察自旋层锁定
DOI：
10.1038/ncomms14216
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发表时间：
2017-01-31
影响因子：
16.6
通讯作者：
Zhou S
中科院分区：
文献类型：
--
作者：
Yao W;Wang E;Huang H;Deng K;Yan M;Zhang K;Miyamoto K;Okuda T;Li L;Wang Y;Gao H;Liu C;Duan W;Zhou S
人们普遍认为，非磁性固体中的自旋极化是由整体晶体空间群的不对称性引起的，这使得自旋电子学材料的研究主要局限于非中心对称材料。最近有人提出，自旋极化基本上源于局部原子位置的不对称，因此中心对称材料可能表现出以前被忽视的自旋极化。本文利用自旋和角分辨光发射光谱，在单层、中心对称和半导体PtSe2薄膜中观察到螺旋自旋织构，而没有传统Rashba效应中的自旋分裂特征（R-1）。第一性原理计算和有效解析模型分析表明，局域偶极子诱导Rashba效应（R-2）具有自旋层锁定：相反自旋在能量上简并，而在顶部和底部Se层中空间分离。这些结果不仅丰富了我们对自旋极化物理的理解，而且可能在电可调谐自旋电子学中得到应用。
The generally accepted view that spin polarization in non-magnetic solids is induced by the asymmetry of the global crystal space group has limited the search for spintronics materials mainly to non-centrosymmetric materials. In recent times it has been suggested that spin polarization originates fundamentally from local atomic site asymmetries and therefore centrosymmetric materials may exhibit previously overlooked spin polarizations. Here, by using spin- and angle-resolved photoemission spectroscopy, we report the observation of helical spin texture in monolayer, centrosymmetric and semiconducting PtSe2 film without the characteristic spin splitting in conventional Rashba effect (R-1). First-principles calculations and effective analytical model analysis suggest local dipole induced Rashba effect (R-2) with spin-layer locking: opposite spins are degenerate in energy, while spatially separated in the top and bottom Se layers. These results not only enrich our understanding of the spin polarization physics but also may find applications in electrically tunable spintronics.