论文标题
电子音波耦合和拓扑晶体绝缘子中的频段反转的类似谐振的光学观察PB $ _ {1-x} $
Electron-phonon coupling and a resonant-like optical observation of a band inversion in topological crystalline insulator Pb$_{1-x}$Sn$_x$Se
论文作者
论文摘要
pb $ _ {0.865} $ sn $ _ {0.135} $ se和pb $ _ {0.75} $ sn $ _ {0.25} $ se solid解决方案的光学反射率在THZ光谱区域中测量与40 k. 280 k的温度分析范围，在THZ光谱区域中测量pb $ _ {0.75} $ sn $ _ {0.25} $ se数据在动态介电函数形式主义中执行的数据揭示了由于电子 - 音波耦合而导致的新效果，从而导致能量差距的Lo子声音频率的谐振变化，以使能量隙的频率变化等于零或lo phonon能量。对于Pb $ _ {0.865} $ sn $ _ {0.135} $ SE，这种效果不存在，该效果在所有温度下都表现出带有微不足道的带订购的开放能量差距。这些结果表明，THZ范围的反射率构成了一种多功能实验方法，用于精确确定狭窄间隙拓扑材料中的频带反转。对于pb $ _ {0.75} $ sn $ _ {0.25} $ se从微不足道绝缘子到拓扑结晶绝缘子阶段的过渡在温度t $ _0 $ =（172 $ \ pm $ 2）K。
The optical reflectivity of Pb$_{0.865}$Sn$_{0.135}$Se and Pb$_{0.75}$Sn$_{0.25}$Se solid solutions was measured in the THz spectral region energetically corresponding to bulk optical phonon excitations and in the temperature range from 40 K to 280 K. The analysis of Pb$_{0.75}$Sn$_{0.25}$Se data performed within the dynamic dielectric function formalism revealed a new effect due to the electron-phonon coupling resulting in resonant changes of LO phonon frequency for energy gap equal to zero or to LO phonon energy. This effect is absent for Pb$_{0.865}$Sn$_{0.135}$Se that exhibits an open energy gap with trivial band ordering at all temperatures. These results show that reflectivity in the THz range constitute a versatile experimental method for precise determination of band inversion in narrow-gap topological materials. For Pb$_{0.75}$Sn$_{0.25}$Se the transition from trivial insulator to topological crystalline insulator phase takes place at temperature T$_0$ = (172 $\pm$ 2) K.
