Uncovering and tailoring hidden Rashba spin-orbit splitting in centrosymmetric crystals.
Uncovering and tailoring hidden Rashba spin-orbit splitting in centrosymmetric crystals.
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发现并剪裁中心对称晶体中隐藏的拉什巴自旋轨道分裂。
DOI：
10.1038/s41467-019-08836-4
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发表时间：
2019
影响因子：
16.6
通讯作者：
Zunger Alex
中科院分区：
文献类型：
--
作者：
Yuan Linding;Liu Qihang;Zhang Xiuwen;Luo Jun-Wei;Li Shu-Shen;Zunger Alex
具有非中心对称对称性的亚基/扇区的中心对称晶体中隐藏的 Rashba 和 Dresselhaus 自旋分裂（R-2 和 D-2 效应）已在理论上被预测，然后通过实验观察到，但其微观机制仍不清楚。在这里，我们证明 R-2 效应中的自旋分裂是由特定的对称性强制的，例如本示例中的非对称对称性，这确保相关的自旋波函数仅在两个反演伙伴扇区之一上空间分离，从而避免补偿。我们进一步表明，传统 Rashba (R-1) 效应的有效哈密顿量也适用于 R-2 效应，但将对称破缺电场应用于 R-2 化合物会产生与将电场应用于普通的非 R-2 中心对称化合物不同的自旋分裂模式。这一发现为 R-1 效应和 R-2 效应建立了一个共同的基本来源，两者都源于局部扇区对称性，而不是全局晶体对称性本身。
Hidden Rashba and Dresselhaus spin splittings in centrosymmetric crystals with subunits/sectors having non-centrosymmetric symmetries (the R-2 and D-2 effects) have been predicted theoretically and then observed experimentally, but the microscopic mechanism remains unclear. Here we demonstrate that the spin splitting in the R-2 effect is enforced by specific symmetries, such as non-symmorphic symmetry in the present example, which ensures that the pertinent spin wavefunctions segregate spatially on just one of the two inversion-partner sectors and thus avoid compensation. We further show that the effective Hamiltonian for the conventional Rashba (R-1) effect is also applicable for the R-2 effect, but applying a symmetry-breaking electric field to a R-2 compound produces a different spin-splitting pattern than applying a field to a trivial, non-R-2, centrosymmetric compound. This finding establishes a common fundamental source for the R-1 effect and the R-2 effect, both originating from local sector symmetries rather than from the global crystal symmetry per se.