Pan Jiayun, Karki Amar, Plummer E W, Jin Rongying
Department of Physics and Astronomy, Louisiana State University, Baton Rouge 70803, United States of America.
J Phys Condens Matter. 2017 Dec 6;29(48):485702. doi: 10.1088/1361-648X/aa958f. Epub 2017 Nov 9.
CaPtAs(FeAs) is a unique parent compound for superconductivity, which consists of both semiconducting PtAs and metallic FeAs layers. We report the observation of superconductivity induced via chemical doping in either Ca site using rare-earth (RE) elements (RE = La, Gd) or Fe site using Pt. The interlayer distance and the normal-state physical properties of the doped system change correspondingly. The coupled changes include (1) superconducting transition temperature T increases with increasing both doping concentration and interlayer distance, (2) our T value is higher than previously reported maximum value for Pt doping in the Fe site, (3) both the normal-state in-plane resistivity and out-of-plane resistivity change from non-metallic to metallic behavior with increasing doping concentration and T , and (4) the transverse in-plane magnetoresistance (MR) changes from linear-field dependence to quadratic behavior upon increasing T . For La-doped compound with the highest T (~35 K), upper critical fields ([Formula: see text], [Formula: see text]), coherence lengths (ξ , ξ ), and in-plane penetration depth (λ ) are estimated. We discuss the relationship between chemical doping, interlayer distance, and physical properties in this system.
CaPtAs(FeAs)是一种独特的超导母体化合物，它由半导体PtAs层和金属FeAs层组成。我们报告了通过在Ca位点使用稀土（RE）元素（RE = La、Gd）或在Fe位点使用Pt进行化学掺杂诱导超导性的观测结果。掺杂体系的层间距和正常态物理性质相应地发生变化。这些耦合变化包括：（1）超导转变温度T随着掺杂浓度和层间距的增加而升高；（2）我们的T值高于先前报道的Fe位点Pt掺杂的最大值；（3）随着掺杂浓度和T的增加，正常态面内电阻率和面外电阻率都从非金属行为转变为金属行为；（4）随着T的增加，横向面内磁阻（MR）从线性场依赖转变为二次行为。对于T最高（约35 K）的La掺杂化合物，估计了上临界场（[公式：见正文]，[公式：见正文]）、相干长度（ξ ，ξ ）和面内穿透深度（λ ）。我们讨论了该体系中化学掺杂、层间距和物理性质之间的关系。
