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Exotic Dielectric Behaviors Induced by Pseudo-Spin Texture in Magnetic Twisted Bilayer
Chinese Physics Letters ( IF 3.5 ) Pub Date : 2021-03-25 , DOI: 10.1088/0256-307x/38/3/037501
Yu-Hao Shen 1 , Wen-Yi Tong 1 , He Hu 1 , Jun-Ding Zheng 1 , Chun-Gang Duan 1, 2
Affiliation  

Twisted van der Waals bilayers provide an ideal platform to study the electron correlation in solids. Of particular interest is the 30 twisted bilayer honeycomb lattice system, which possesses an incommensurate moir pattern, and uncommon electronic behaviors may appear due to the absence of phase coherence. Such a system is extremely sensitive to further twist and many intriguing phenomena will occur. Based on first-principles calculations we show that, for further twist near 30, there could induce dramatically different dielectric behaviors of electron between left and right-twisted cases. Specifically, it is found that the left and right twists show suppressed and amplified dielectric response under vertical electric field, respectively. Further analysis demonstrate that such an exotic dielectric property can be attributed to the stacking dependent charge redistribution due to twist, which forms twist-dependent pseudospin textures. We will show that such pseudospin textures are robust under small electric field. As a result, for the right-twisted case, there is almost no electric dipole formation exceeding the monolayer thickness when the electric field is applied. Whereas for the left case, the system could even demonstrate negative susceptibility, i.e., the induced polarization is opposite to the applied field, which is very rare in the nature. Such findings not only enrich our understanding on moir systems but also open an appealing route toward functional 2D materials design for electronic, optical and even energy storage devices.



中文翻译:

磁性扭曲双层中由伪自旋纹理引起的奇异介电行为

扭曲的范德华双层为研究固体中的电子相关性提供了一个理想的平台。特别令人感兴趣的是 30 个扭曲的双层蜂窝晶格系统,它具有不相称的莫尔图案,并且由于缺乏相干性,可能会出现不常见的电子行为。这样的系统对进一步的扭曲极为敏感,并且会发生许多有趣的现象。基于第一性原理计算,我们表明,对于 30 附近的进一步扭曲,左右扭曲情况之间可能会引起电子的显着不同的介电行为。具体来说,发现左右扭曲分别在垂直电场下显示出抑制和放大的介电响应。进一步的分析表明,这种奇异的介电特性可归因于扭曲导致的堆叠相关电荷重新分布,从而形成扭曲相关的赝自旋纹理。我们将证明这种赝自旋纹理在小电场下是稳健的。结果,对于右扭曲的情况,当施加电场时,几乎没有超过单层厚度的电偶极子形成。而对于左边的情况,系统甚至可以表现出负磁化率,即诱导极化与外加场相反,这在自然界中是非常罕见的。这些发现不仅丰富了我们对云纹系统的理解,而且为电子、光学甚至储能设备的功能二维材料设计开辟了一条有吸引力的途径。形成与扭曲相关的伪自旋纹理。我们将证明这种赝自旋纹理在小电场下是稳健的。结果,对于右扭曲的情况,当施加电场时,几乎没有超过单层厚度的电偶极子形成。而对于左边的情况,系统甚至可以表现出负磁化率,即诱导极化与外加场相反,这在自然界中是非常罕见的。这些发现不仅丰富了我们对云纹系统的理解,而且为电子、光学甚至储能设备的功能二维材料设计开辟了一条有吸引力的途径。形成与扭曲相关的伪自旋纹理。我们将证明这种赝自旋纹理在小电场下是稳健的。结果,对于右扭曲的情况,当施加电场时,几乎没有超过单层厚度的电偶极子形成。而对于左边的情况,系统甚至可以表现出负磁化率,即诱导极化与外加场相反,这在自然界中是非常罕见的。这些发现不仅丰富了我们对云纹系统的理解,而且为电子、光学甚至储能设备的功能二维材料设计开辟了一条有吸引力的途径。当施加电场时,几乎没有超过单层厚度的电偶极子形成。而对于左边的情况,系统甚至可以表现出负磁化率,即诱导极化与外加场相反,这在自然界中是非常罕见的。这些发现不仅丰富了我们对云纹系统的理解,而且为电子、光学甚至储能设备的功能二维材料设计开辟了一条有吸引力的途径。当施加电场时,几乎没有超过单层厚度的电偶极子形成。而对于左边的情况,系统甚至可以表现出负磁化率,即诱导极化与外加场相反,这在自然界中是非常罕见的。这些发现不仅丰富了我们对云纹系统的理解,而且为电子、光学甚至储能设备的功能二维材料设计开辟了一条有吸引力的途径。

更新日期:2021-03-25
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