论文标题
扭曲的双双层石墨烯中的可调式间和内映的等离子体
Tunable interband and intraband plasmons in twisted double bilayer graphene
论文作者
论文摘要
扭曲的Moire超级晶格中的扁平带支持各种拓扑和强相关的现象，以及易于调谐的电气和光学特性。在这里，我们证明了在扭曲的双重双层石墨烯中的可调，长寿命和平坦的内映射和束带Terahertz等离子体。我们表明，频带间等离子源于状态的关节密度中的van霍夫奇异性以及涉及的一对频带之间的有限浆果连接。我们发现，间隙间等离子模式具有通用分散体，并且血浆间隙由范霍夫奇异性在状态的关节密度中的位置指定。金属Moire系统支持额外的标签内等离子体模式，该模式由于带间相关的影响而在较大的动量极限中变得平坦。我们证明，Moire系统中的未阻塞和平坦的等离子模式是高度可调的，可以通过改变垂直电场和电子掺杂来控制，并且它们持续在各种扭曲角度上。
Flat bands in twisted moire superlattices support a variety of topological and strongly correlated phenomena along with easily tunable electrical and optical properties. Here, we demonstrate the existence of tunable, long-lived, and flat intraband and interband terahertz plasmons in twisted double bilayer graphene. We show that the interband plasmons originate from the presence of a Van Hove singularity in the joint density of states and a finite Berry connection between the pair of bands involved. We find that the gapped interband plasmon mode has a universal dispersion, and the plasmon gap is specified by the location of the Van Hove singularity in the joint density of states. Metallic moire systems support an additional intraband plasmon mode which becomes flat in the large momentum limit because of the influence of the interband correlations. We demonstrate that the undamped and flat plasmon modes in moire systems are highly tunable and can be controlled by varying the vertical electric field and electron doping, and they persist over a wide range of twist angles.
