论文标题
terahertz c轴la $ _ {1.85} $ sr $ _ {0.15} $ cuo $ _4 $
Terahertz third harmonic generation in c-axis La$_{1.85}$Sr$_{0.15}$CuO$_4$
论文作者
论文摘要
Terahertz非线性光学是一种可行的方法，用于审问跨越铁电，电荷密度波和超导性的量子材料中的集体现象。在超导体中，这包括希格斯幅度和约瑟夫森相模式。我们已经调查了最佳掺杂的LA $ _ {1.85} $ sr $ _ {0.15} $ CUO $ _4 $的非线性C轴响应，该反应最高可达$ \ sim $ \ sim $ 80 kv/cm。随着场的增加，我们观察到约瑟夫森等离子体边缘的明显红移，并提高了由第三次谐波产生引起的反射率（在等离子边缘上方）。非单调温度依赖性响应与约瑟夫森等离子体模式（JPM）的非线性驱动相一致，与理论期望进行了比较。我们的结果增加了这样的理解：使用THZ Light，JPM（除了HIGGS模式之外）提供了询问和控制超导属性的途径。
Terahertz nonlinear optics is a viable method to interrogate collective phenomena in quantum materials spanning ferroelectrics, charge-density waves, and superconductivity. In superconductors this includes the Higgs amplitude and Josephson phase modes. We have investigated the nonlinear c-axis response of optimally doped La$_{1.85}$Sr$_{0.15}$CuO$_4$ using high-field THz time domain spectroscopy (THz-TDS) at field strengths up to $\sim$80 kV/cm. With increasing field, we observe a distinct red-shift of the Josephson plasma edge and enhanced reflectivity (above the plasma edge) arising from third harmonic generation. The non-monotonic temperature dependent response is consistent with nonlinear drive of the Josephson Plasma Mode (JPM) as verified with comparison to theoretical expectations. Our results add to the understanding that, using THz light, the JPM (in addition to the Higgs mode) provides a route to interrogate and control superconducting properties.
