Unveiling giant hidden Rashba effects in two-dimensional Si2Bi2
Unveiling giant hidden Rashba effects in two-dimensional Si2Bi2
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DOI：
10.1038/s41699-020-00180-2
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发表时间：
2020-07
影响因子：
9.7
通讯作者：
Seungjun Lee;Young-Kyun Kwon
中科院分区：
文献类型：
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作者：
Seungjun Lee;Young-Kyun Kwon
最近，人们已经知道，在二维材料中隐藏的Rashba（R-2）效应引起了一种称为自旋层锁定（SLL）的物理现象。然而，不仅其潜在的基本机制尚不清楚，而且只有少数材料表现出弱的SLL。本文通过第一性原理密度泛函理论和模型哈密顿计算，揭示了R-2的SLL是由子层-子层相互作用和自旋-轨道耦合之间的竞争决定的，这与Rashba强度有关.此外，轨道角动量分布是实现强R-2超光速的另一个关键。我们认为，2D材料Si_2Bi_2具有强R-2 SLL的理想条件，其Rashba强度估计为2.16 eV，这是迄今为止在2D R-2材料中观察到的最大值。此外，我们揭示了双层结构中的层间相互作用确保了R-2态在空间上相距更远，这意味着在自旋电子学中的潜在应用。
Recently, it has been known that the hidden Rashba (R-2) effect in two-dimensional materials gives rise to a physical phenomenon called spin-layer locking (SLL). However, not only its underlying fundamental mechanism has been unclear, but also there are only a few materials exhibiting weak SLL. Here, through the first-principles density functional theory and model Hamiltonian calculation, we reveal that the R-2 SLL can be determined by the competition between the sublayer–sublayer interaction and the spin–orbit coupling, which is related to the Rashba strength. In addition, the orbital angular momentum distribution is another crucial point to realize the strong R-2 SLL. We propose that a 2D material Si2Bi2possesses an ideal condition for the strong R-2 SLL, whose Rashba strength is evaluated to be 2.16 eVÅ, which is the greatest value ever observed in 2D R-2 materials to the best of our knowledge. Furthermore, we reveal that the interlayer interaction in a bilayer structure ensures R-2 states spatially farther apart, implying a potential application in spintronics.