论文标题
光谱和超快泵探针研究BI $ _2 $ rh $ _3 $ SE $ _2 $：电荷 - 密度 - 波订单的证据
Optical spectroscopy and ultrafast pump-probe study on Bi$_2$Rh$_3$Se$_2$: evidence for charge-density-wave order formation
论文作者
论文摘要
Parkerite-type三元粉红色IDE $ _2 $ rh $ _3 $ se $ _2 $被发现是电荷密度波（CDW）超导体。但是，关于在240 K处观察到的相变的辩论是归因于CDW顺序的形成。为了解决这个问题，我们对BI $ _2 $ RH $ _3 $ SE $ _2 $的单晶样品进行了光谱和超快泵送测量。我们的光导率测量清楚地揭示了仅在低能量下与相关光谱变化的能量隙的形成，从而为240 K时CDW相变提供了有力的证据。时间分辨分解的泵探针测量为CDW相变的进一步支持提供了进一步的支持。从光诱导的反射率中提取的准粒子的幅度和松弛时间在过渡温度附近显示出强烈的增强，从而进一步证明了CDW能量隙的形成。此外，在低温下泵探针时间延迟中的振荡中确定了集体模式。这种模式在升高温度下逐渐降低的模式可以自然归因于CDW状态的振幅模式。
The parkerite-type ternary chalcogenide Bi$_2$Rh$_3$Se$_2$ was discovered to be a charge density wave (CDW) superconductor. However, there was a debate on whether the observed phase transition at 240 K could be attributed to the formation of CDW order. To address the issue, we performed optical spectroscopy and ultrafast pump-probe measurements on single crystal samples of Bi$_2$Rh$_3$Se$_2$. Our optical conductivity measurement reveals clearly the formation of an energy gap with associated spectral change only at low energies, yielding strong evidence for a CDW phase transition at 240 K. Time resolved pump-probe measurement provides further support for the CDW phase transition. The amplitude and relaxation time of quasiparticles extracted from the photoinduced reflectivity show strong enhancement near transition temperature, yielding further evidence for the CDW energy gap formation. Additionally, a collective mode is identified from the oscillations in the pump-probe time delay at low temperature. This mode, whose frequency decreases gradually at elevated temperature, could be naturally attributed to the amplitude mode of CDW state.
