Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Phys Rev Lett. 2014 Jan 31;112(4):047005. doi: 10.1103/PhysRevLett.112.047005.
We use multiscale techniques to determine the extent of local inhomogeneity and superconductivity in Ca0.86Pr0.14Fe2As2 single crystal. The inhomogeneity is manifested as a spatial variation of the praseodymium concentration, local density of states, and superconducting order parameter. We show that the high-Tc superconductivity emerges from cloverlike defects associated with Pr dopants. The highest Tc is observed in both the tetragonal and collapsed tetragonal phases, and its filamentary nature is a consequence of nonuniform Pr distribution that develops localized, isolated superconducting regions within the crystals.
我们使用多尺度技术来确定 Ca0.86Pr0.14Fe2As2 单晶中局部非均匀性和超导性的程度。非均匀性表现为镨浓度、局域态密度和超导序参量的空间变化。我们表明，高温超导性源自与 Pr 掺杂剂相关的三叶草状缺陷。在四方相和塌缩四方相都观察到了最高 Tc，其纤维状性质是 Pr 分布不均匀的结果，这种不均匀性在晶体内部形成了局部的、孤立的超导区域。
