Herein, studies of the cyclotron resonance (CR) in thick ${\text{Cd}}_x{\text{Hg}}_{1-x}\text{Te}$ films with different cadmium contents corresponding to materials with and without band inversion, as well as critical content corresponding to an almost linear energy dispersion are presented. The results demonstrate that the formation of 2D topological surface states requires sharp interfaces between layers with and without band inversion, in which case the corresponding CR is clearly observed for the out‐of‐plane orientation of magnetic field but does not show up for an in‐plane orientation. In contrast, all samples having more conventional technological design with smooth interfaces (i.e., containing regions of ${\text{Cd}}_x{\text{Hg}}_{1-x}\text{Te}$ with gradually changing Cd content x) show equally pronounced CR in both in‐plane and out‐of‐plane magnetic field revealing that CR is excited in effectively 3D states. Modeling of the surface states for different film designs supports main observations. In all samples, additional broad helicity‐independent resonances are observed, which are attributed to photoionization and magnetic freeze‐out of impurity states.

中文翻译：

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太赫兹磁共振波谱从CdxHg1-xTe厚膜的拓扑表面态回旋加速器共振。

在这里，对厚壁回旋共振（CR）的研究 ${\text{光盘}}_X{\text{汞}}_{\mathrm{1个}-X}\text{特}$提出了不同镉含量的薄膜，分别对应于带和不带反转的材料，以及对应于几乎线性能量色散的临界含量。结果表明，二维拓扑表面状态的形成需要在带反转和不带反转的情况下在层之间形成清晰的界面，在这种情况下，可以清楚地观察到磁场的面外取向对应的CR，而对于in则不显示平面方向。相反，所有样品均具有更常规的技术设计，且界面光滑（即包含${\text{光盘}}_X{\text{汞}}_{\mathrm{1个}-X}\text{特}$随着Cd含量的逐渐变化x）在平面内和平面外磁场中均显示出同样显着的CR，表明CR在有效的3D状态下被激发。不同膜设计的表面状态建模支持主要观察。在所有样品中，均观察到其他不依赖螺旋的广泛共振，这归因于杂质态的光电离和磁性冻结。