Naturally occurring hyperbolic plasmonic media is rare, and was only recently observed in the $1{\mathrm{T}}^{\prime }$ phase of ${\mathrm{WTe}}_2$. We elucidate on the physical origin of this strong infrared hyperbolic response, and attribute it to band-nested anisotropic interband transitions. Such a phenomenon does not occur in general anisotropic materials, at least not in their pristine state. However, band-nested anisotropic interband transitions can in principle be induced via proper electronic band nesting. We illustrate this principle and demonstrate a topological elliptic-to-hyperbolic transition in ${\mathrm{MoTe}}_2$ via strain engineering, which is otherwise nonhyperbolic.

中文翻译：

---

电子带嵌套引起的二维过渡金属二碲化物的双曲性

天然存在的双曲线等离子体介质很少见，仅在最近才被发现。 $\mathrm{1个}{\mathrm{Ť}}^{\prime }$ 的阶段 ${\mathrm{威特}}_2$。我们阐明了这种强烈的红外双曲线响应的物理起源，并将其归因于带嵌套的各向异性带间跃迁。这种现象在一般的各向异性材料中不会发生，至少在其原始状态下不会发生。但是，原则上可以通过适当的电子频带嵌套来诱发频带嵌套的各向异性频带间过渡。我们说明了这一原理，并证明了从椭圆到双曲的拓扑过渡${\mathrm{Te}}_2$ 通过应变工程，否则是非双曲线的。