论文标题
直接观察电子掺杂的铜氧化铜SR $ _ {1-x} $ nd $ _x $ cuo $ _2 $
Direct observation of nodeless superconductivity and phonon modes in electron-doped copper oxide Sr$_{1-x}$Nd$_x$CuO$_2$
论文作者
论文摘要
这些材料中晶体结构的明显复杂性阻碍了对丘陵高温超导性的微观理解。我们使用扫描隧道显微镜和光谱法来研究电子掺杂的氧化铜化合物SR $ _ {1-x} $ nd $ _x $ _x $ cuo $ _2 $，它只有将Cuo $ $ _2 $的裸露阳离子分开，因此所有最简单的Infinite-Infinite-layer-layer结构是所有熟食库中最简单的cuprate cuprcrate cuprcrate cuprcrate cuprcrate。超导状态下主要CUO $ _2 $平面的隧道电导光谱揭示了无节性配对缝隙的直接证据，无论其幅度与局部三价新近山的掺杂的变化如何。此外，观察到三种不同的骨气模式是超导间隙外的多个峰值 - 浸入特征，它们各自的能量很少取决于空间变化的间隙。除了能量与外部，弯曲和拉伸的铜氧化物声子相同的骨气模式外，我们的发现表明它们来自晶格振动而不是自旋激发的起源。
The microscopic understanding of high-temperature superconductivity in cuprates has been hindered by the apparent complexity of crystal structures in these materials. We used scanning tunneling microscopy and spectroscopy to study an electron-doped copper oxide compound Sr$_{1-x}$Nd$_x$CuO$_2$ that has only bare cations separating the CuO$_2$ planes and thus the simplest infinite-layer structure among all cuprate superconductors. Tunneling conductance spectra of the major CuO$_2$ planes in the superconducting state revealed direct evidence for a nodeless pairing gap, regardless of variation of its magnitude with the local doping of trivalent neodymium. Furthermore, three distinct bosonic modes are observed as multiple peak-dip-hump features outside the superconducting gaps and their respective energies depend little on the spatially varying gaps. Along with the bosonic modes with energies identical to those of the external, bending and stretching phonons of copper oxides, our findings indicate their origin from lattice vibrations rather than spin excitations.
