论文标题
Terahertz磁镜从拓扑表面状态的CD $ _x $ hg $ _ {1-x} $ te的拓扑表面状态产生的磁镜
Terahertz Magnetospectroscopy of Cyclotron Resonances from Topological Surface States in Thick Films of Cd$_x$Hg$_{1-x}$Te
论文作者
论文摘要
我们介绍了厚CD $ _x $ hg $ _ {1-x} $ te薄膜的转基因共振（CR）的研究，其摄入量不同的镉浓度对应于倒置和正常带顺序，以及几乎是线性的能量分散剂。我们的结果表明，二维拓扑表面状态的形成需要在具有倒置和正常带顺序的层之间锐利的接口，在这种情况下，对于磁场的平面外向而言，清楚地观察到了相应的CR，但并未显示出平面方向。相比之下，所有具有更传统的技术设计的样品（即包含CD $ _X $ _x $ hg $ _ {1-x} $带有逐渐变化的CD Content $ x $的区域都显示出在平面内和平面磁场中同样明显的CR，表明CR在三维状态中都令人兴奋。对不同膜设计的表面状态建模支持我们的主要观察结果。在所有样品中，我们都会观察到额外的宽螺旋性无关共振，这些共振归因于杂质状态的光电发和磁冻结。
We present studies of the cyclotron resonance (CR) in thick Cd$_x$Hg$_{1-x}$Te films with different cadmium concentrations corresponding to inverted and normal band order, as well as to an almost linear energy dispersion. Our results demonstrate that formation of two-dimensional topological surface states requires sharp interfaces between layers with inverted and normal band order, in which case the corresponding CR is clearly observed for the out-of-plane orientation of magnetic field, but does not show up for an in-plane orientation. By contrast, all samples having more conventional technological design with smooth interfaces (i.e., containing regions of Cd$_x$Hg$_{1-x}$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 three-dimensional states. Modeling of the surface states for different film designs supports our main observations. In all samples, we observe additional broad helicity-independent resonances which are attributed to photo-ionization and magnetic freeze-out of impurity states.
