论文标题
二维超倾斜的狄拉克带中的异常声等离子体
Anomalous acoustic plasmons in two-dimensional over-tilted Dirac bands
论文作者
论文摘要
II型狄拉克锥的过度倾斜导致了各种引人入胜的量子现象。在这里，我们发现两个异常的声学等离子体（AAP）是由二维（2D）类型-II Dirac锥的独特几何形状决定的，远远超出了常规的$ \ text {\ ensureMath {\ ensuremath {\ sqrt {\ sqrt {q}}}}}}} $ plasmon。一个AAP源自一个dirac点的两个口袋的强杂交，而另一个则归因于开放费米表面周围的带相关的显着增强。值得注意的是，由于手性电子分散，等离子沿着倾斜方向表现出山谷依赖性手性。同时，我们通过调整间隙和介电底物来讨论等离子体分散和寿命的可调性。我们的工作提供了一种有前途的方法来在狄拉克材料中产生新的等离子体。
The over-tilting of type-II Dirac cones has led to various fascinating quantum phenomena. Here we find two anomalous acoustic plasmons (AAPs) are dictated by the distinct geometry of two-dimensional (2D) type-II Dirac cones, far beyond the conventional $\text{\ensuremath{\sqrt{q}}}$ plasmon. One AAP originates from the strong hybridization of two pockets at one Dirac point, whereas the other is attributed to the significant enhancement of the band correlation around the open Fermi surface. Remarkably, the plasmons exhibit valley-dependent chirality along the tilting direction due to the chiral electron dispersion. Meanwhile, we discuss the tunability of plasmon dispersion and lifetime by tuning the gap and dielectric substrate. Our work provides a promising way to generate the novel plasmons in Dirac materials.
