Katsumi Kota, Tsuji Naoto, Hamada Yuki I, Matsunaga Ryusuke, Schneeloch John, Zhong Ruidan D, Gu Genda D, Aoki Hideo, Gallais Yann, Shimano Ryo
Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan.
RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan.
Phys Rev Lett. 2018 Mar 16;120(11):117001. doi: 10.1103/PhysRevLett.120.117001.
We investigate the terahertz (THz)-pulse-driven nonlinear response in the d-wave cuprate superconductor Bi_{2}Sr_{2}CaCu_{2}O_{8+x} (Bi2212) using a THz pump near-infrared probe scheme in the time domain. We observe an oscillatory behavior of the optical reflectivity that follows the THz electric field squared and is markedly enhanced below T_{c}. The corresponding third-order nonlinear effect exhibits both A_{1g} and B_{1g} symmetry components, which are decomposed from polarization-resolved measurements. A comparison with a BCS calculation of the nonlinear susceptibility indicates that the A_{1g} component is associated with the Higgs mode of the d-wave order parameter.
我们利用太赫兹泵浦近红外探测时域方案，研究了d波铜酸盐超导体Bi₂Sr₂CaCu₂O₈₊ₓ（Bi2212）中太赫兹（THz）脉冲驱动的非线性响应。我们观察到光反射率的振荡行为，它遵循太赫兹电场平方，并且在临界温度Tc以下显著增强。相应的三阶非线性效应表现出A₁g和B₁g对称分量，这些分量是从偏振分辨测量中分解出来的。与非线性磁化率的BCS计算结果比较表明，A₁g分量与d波序参量的希格斯模式相关。
