具有反转能带的二维材料中因墨西哥帽色散产生的带间等离激元
Interband plasmons due to Mexican hat dispersion in two-dimensional materials with inverted bands
AI总结：
研究具有墨西哥帽色散的二维反转能带拓扑材料，发现其可增强带间等离激元、降低阻尼并产生额外谱分支，还揭示了等离激元谱与联合态密度奇点、带间量子度量的关联。
AI中文摘要：
具有墨西哥帽色散的二维拓扑材料展现出众多非平庸特性，如k空间中的双值等能 contour、电子与空穴态的强混合、态密度中的范霍夫奇点以及特定的量子几何特性。我们发现，由于这些特性，当电子-空穴对称性破缺时，墨西哥帽色散会显著增强带间等离激元，降低其阻尼，并产生等离激元谱的额外分支。等离激元谱被限制在有限的波矢范围内，其边界取决于电子-电子相互作用的强度。我们还揭示了等离激元谱特性与有限等离激元波矢q下的联合态密度奇点、以及同样依赖于q的带间量子度量之间的关系。
英文摘要：
Two-dimensional topological materials with Mexican-hat dispersion exhibit numerous nontrivial features, such as double-valued isoenergetic contours in k-space, strong mixing of electron and hole states, a van Hove singularity in the density of states, and specific quantum geometric properties. We find that, due to these features, Mexican-hat dispersion significantly strengthens interband plasmons, reduces their damping, and gives rise to an additional branch of the plasmon spectrum when electron-hole symmetry is broken. The plasmon spectra are limited to a finite range of the wave vector, the boundaries of which depend on the strength of the electron-electron interaction. We also reveal a relationship between the features of the plasmon spectrum and singularities of the joint density of states with a finite plasmon wave vector q, as well as features of the interband quantum metric, which also depend on q.
