电子型最佳掺杂高温超导体Nd_(1.85)Ce_(0.15)CuO_(4-δ)中的磁激发谱

Spin excitations in the optimally electron-doped superconductor Nd_(1.85)Ce_(0.15)CuO_(4-δ)

文章作者用非弹性中子散射探测了电子型最佳掺杂高温超导体Nd1.85Ce0.15CuO4-δ(Tc=25K)的磁激发谱.当样品的温度从正常态逐渐降低至超导态时,在以波矢Q=(π,,π0)为中心的区域,系统打开了一个小于4m eV的自旋隙,与此同时,在9.5m eV附近出现了一个"中子-自旋磁共振峰",并且"共振峰"的强度随温度的变化关系类似于超导序参量在超导相变发生时的变化,这一点与以前发现的各种空穴型超导体以及电子型超导体Pr0.88LaCe0.12CuO4中的"共振峰"的性质极为相似.因此可以说明"共振峰"是所有高温超导体的共性,并且对高温超导电性的形成有着非常关键的作用.

The magnetic excitation spectrum of an optimally electron-doped superconductor Nd1.85Ce0.15CuO4-δ at Tc =25K has been measured using inelastic neutron scattering. On cooling from the normal to the superconducting state, a spin gap below 4meV appears in the system and a resonance occurs at about 9.5meV centered at Q = （ 1/2,1/2,0）. The intensity of the resonance evolves like a superconducting order parameter, similar to those for hole-doped superconductors and electron-doped Pr0.88 LaCe0.12 CuO4 . The resonance is therefore a universal feature of cuprate superconductors, and seems to be fundamental to the mechanism of high-Tc superconductivity.