Emerging flat bands in large-angle twisted bi-layer graphene under pressure
Emerging flat bands in large-angle twisted bi-layer graphene under pressure
复制标题
压力下大角度扭曲双层石墨烯中出现的平带
DOI：
10.1039/d1nr00220a
复制
发表时间：
2021
期刊：
影响因子：
6.7
通讯作者：
Zhu Yanwu
中科院分区：
文献类型：
--
作者：
Ge Liangbing;Ni Kun;Wu Xiaojun;Fu Zhengping;Lu Yalin;Zhu Yanwu
魔角扭曲双层石墨烯由于具有非常规的超导性和相关绝缘性等奇异性质，最近的实验引起了人们的广泛关注。这些现象通常在魔角小于1.1°时发现。然而，制备具有小魔角的精确控制的双层石墨烯是具有挑战性的。采用密度泛函理论研究了大角度扭曲双层石墨烯在压力作用下的电子性质。我们证明了大角度TBG可以在压力下显示费米能级附近的平坦带，这也可能引起有趣的性质，如超导性，这些性质仅在环境压力下的小角度TBG中发现。费米速度被发现与大扭曲角的压力单调下降，例如，21.8度我们的工作表明，施加压力提供了机会，在更大的角度TBG的平带工程，并支持在相关研究的进一步探索。
Recent experiments on magic-angle twisted bi-layer graphene have attracted intensive attention due to exotic properties such as unconventional superconductivity and correlated insulation. These phenomena were often found at a magic angle less than 1.1°. However, the preparation of precisely controlled bi-layer graphene with a small magic angle is challenging. In this work, electronic properties of large-angle twisted bi-layer graphene (TBG) under pressure are investigated with density functional theory. We demonstrate that large-angle TBG can display flat bands nearby the Fermi level under pressure, which may also induce interesting properties such as superconductivity which have only been found in small-angle TBG at ambient pressure. The Fermi velocity is found to decrease monotonously with pressure for large twisted angles, e.g., 21.8°. Our work indicates that applying pressure provides opportunities for flat-band engineering in larger angle TBG and supports further exploration in related investigations.