arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2209.14722cond-mat.mtrl-sci
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通过反转电场方向来切换Rashba自旋分裂

Switching Rashba spin-splitting by reversing electric-field direction

San-Dong Guo, Jing-Xin Zhu, Hao-Tian Guo, Bing Wang, Guang-Zhao Wang, Yee-Sin Ang

摘要:

Rashba自旋分裂的控制对于纳米自旋电子技术的发展至关重要。在这里,提出了Rashba自旋分裂可以通过反转电场方向来打开和关闭。通过第一性原理计算,我们的建议是说明了一个具体的例子Janus单层RbKNaBi。所设计的RbKNaBi具有动力学、热学和力学稳定性,是一种在费米能级附近具有Rashba自旋分裂的大能隙量子自旋霍尔绝缘体(QSHI)。由于底部和顶部原子之间的电负性差异非常小,因此预测了小的内建电场,这是通过实验上可用的电场强度来切换Rashba自旋分裂的关键。由于平面外结构的不对称性,Janus单层在施加相同大小但不同方向的外电场$E$($z$或$-z$)时具有独特的行为。结果表明,正的$E$使Rashba能量($E_R$)和Rashba常数($α_R$)增加,而负的$E$则抑制Rashba分裂消失,然后又出现.在一定的$E$区域(0.15 $\mathrm{V/Å}$至0.25 $\mathrm{V/Å}$)中,仅通过反转电场方向就可以实现切换Rashba自旋分裂。此外,还预测了压电应变系数$d_{11}$和$d_{31}$(5.52 pm/V和-0.41 pm/V),其值高于或高于许多二维材料的值。通过压电效应,该应变还可以用于调节RbKNaBi的Rashba自旋分裂。此外,还提出了一种可能的自旋电子器件来实现自旋电子开关的功能。

英文摘要:

The manipulation of the Rashba spin-splitting is crucial for the development of nanospintronic technology. Here, it is proposed that the Rashba spin-splitting can be turned on and off by reversing electric-field direction. By the first-principle calculations, our proposal is illustrated by a concrete example of Janus monolayer RbKNaBi. The designed RbKNaBi possesses dynamical, thermal and mechanical stability, and is a large-gap quantum spin Hall insulator (QSHI) with Rashba spin-splitting near the Fermi level. A small built-in electric field is predicted due to very small electronegativity difference between the bottom and top atoms, which is very key to switch Rashba spin-splitting through the experimentally available electric field intensity. Due to out-of-plane structural asymmetry, the Janus monolayer has distinctive behaviors by applying external electric field $E$ with the same magnitude but different directions ($z$ or $-z$). Our results reveal that the Rashba energy ($E_R$) and Rashba constant ($α_R$) are increased by the positive $E$, while a negative $E$ suppresses the Rashba splitting to disappear, and then appears again. In a certain $E$ region (0.15 $\mathrm{V/Å}$ to 0.25 $\mathrm{V/Å}$), switching Rashba spin-splitting can be achieved by only reversing electric-field direction. Besides, the piezoelectric strain coefficients $d_{11}$ and $d_{31}$ (5.52 pm/V and -0.41 pm/V) are predicted, which are higher than or compared with those of many 2D materials. By piezoelectric effect, the strain can also be used to tune Rashba spin-splitting of RbKNaBi. Moreover, a possible spintronic device is proposed to realize the function of spintronic switch.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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