arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.14557cond-mat.mes-hallcond-mat.other
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自旋-动量锁定的从头算k.p理论:在拓扑表面态中的应用

Ab initio k.p theory of spin-momentum locking: Application to topological surface states

I. A. Nechaev, E. E. Krasovskii

摘要:

基于从头算相对论${\mathbf k}\cdot{\mathbf p}$理论,我们在$\mathbf{k}$中导出了三维拓扑绝缘体表面态的有效双带模型.它提供了一个全面的描述的表面自旋结构,其特征在于动量和自旋之间的非正交性。我们表明,振荡的非正交性与极角的$\mathbf{k}$与$π/3$周期性可以被看作是由于有效的六重对称的自旋轨道磁场的场矢量的五倍和七倍绕组的$\mathbf{k}$每一个单一的旋转。由于经典Rashba场的主导作用,仍然存在单绕组螺旋自旋结构,但与动量和自旋之间的正交锁定有周期性的几度偏离。

英文摘要:

Based on ab initio relativistic ${\mathbf k}\cdot{\mathbf p}$ theory, we derive an effective two-band model for surface states of three-dimensional topological insulators up to seventh order in $\mathbf{k}$. It provides a comprehensive description of the surface spin structure characterized by a non-orthogonality between momentum and spin. We show that the oscillation of the non-orthogonality with the polar angle of $\mathbf{k}$ with a $π/3$ periodicity can be seen as due to effective six-fold symmetric spin-orbit magnetic fields with a quintuple and septuple winding of the field vectors per single rotation of $\mathbf{k}$. Owing to the dominant effect of the classical Rashba field, there remains a single-winding helical spin structure but with a periodic few-degree deviation from the orthogonal locking between momentum and spin.

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