标题： 从非掺杂超导体 T'-La$_{1.8}$Eu$_{0.2}$CuO$_4$中杂质效应研究配对对称性 显示英文标题

标题： Pairing Symmetry Studied from Impurity Effects in the Undoped Superconductor T'-La$_{1.8}$Eu$_{0.2}$CuO$_4$

摘要： 我们研究了磁性Ni杂质和非磁性Zn杂质对未掺杂T'-La$_{1.8}$Eu$_{0.2}$CuO$_4$(T'-LECO) 以Nd$_2$CuO$_4$结构的影响，使用多晶块状样品，以明确配对对称性。 通过研究发现，Ni和Zn杂质对超导转变温度$T_\mathrm{c}$的抑制率几乎相同，并且与空穴掺杂的T-La$_{2-x}$Sr$_{x}$CuO$_4$具有K$_2$NiF$_4$结构的最优掺杂和过掺杂区域中的抑制率非常相似。 这些结果强烈表明，未掺杂的T'-LECO中的超导性具有$d$波对称性，并由自旋涨落介导。 显示英文摘要

摘要： We have investigated the effects of magnetic Ni and nonmagnetic Zn impurities on the superconductivity in undoped T'-La$_{1.8}$Eu$_{0.2}$CuO$_4$ (T'-LECO) with the Nd$_2$CuO$_4$-type structure, using the polycrystalline bulk samples, to clarify the pairing symmetry. It has been found that both suppression rates of the superconducting transition temperature $T_\mathrm{c}$ by Ni and Zn impurities are nearly the same and are very similar to those in the optimally doped and overdoped regimes of hole-doped T-La$_{2-x}$Sr$_{x}$CuO$_4$ with the K$_2$NiF$_4$-type structure. These results strongly suggest that the superconductivity in undoped T'-LECO is of the $d$-wave symmetry and is mediated by the spin fluctuation.