Linkage between scattering rates and superconductivity in doped ferropnictides
Linkage between scattering rates and superconductivity in doped ferropnictides
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DOI：
10.1103/physrevb.103.155119
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发表时间：
2021-04-12
影响因子：
3.7
通讯作者：
Buechner, B.
中科院分区：
文献类型：
--
作者：
Fink, J.;Rienks, E. D. L.;Buechner, B.
我们报告了一系列的空穴和电子掺杂的铁基超导体，它们的母体化合物BaFe 2As 2，和它们的表兄弟BaCr 2As 2和BaCo 2As 2的角分辨光电子能谱研究。我们专注于内孔口袋，这是在这些化合物的热点。更具体地，我们确定能量（E）依赖的散射率Gamma（E）作为3d计数的函数。此外，对于化合物K_（0.4）Ba_（0.6）Fe_2As_2和BaCr_2As_2，我们导出了重整化函数Z（E）和自能函数Im_Sigma（E）虚部的能量依赖关系。我们得到了非费米类液体的能量散射率γ（E >> k（B）T），与掺杂浓度无关。主要结果是斜率β = Gamma（E >> k（B）T）/E在最佳掺杂附近达到其最大值，并且与超导转变温度成比例。这支持了这些材料的超导性的自旋涨落模型。在最佳空穴掺杂的化合物中，内空穴袋的散射率的斜率比接近1的普朗克极限Gamma（E）/E大约3倍。这一结果与重整化函数Z（E）的能量依赖性一起，表明在正常状态下非常不相干的电荷载流子在低温下转变为相干的非常规超导状态。
We report an angle-resolved photoemission study of a series of hole- and electron-doped iron-based superconductors, their parent compound BaFe2As2, and their cousins BaCr2As2 and BaCo2As2. We focus on the inner hole pocket, which is the hot spot in these compounds. More specifically, we determine the energy (E)-dependent scattering rate Gamma(E) as a function of the 3d count. Moreover, for the compounds K0.4Ba0.6Fe2As2 and BaCr2As2, we derive the energy dependence of the renormalization function Z(E) and the imaginary part of the self-energy function Im Sigma(E). We obtain a non-Fermi liquidlike linear in energy scattering rate Gamma(E >> k(B)T ), independent of the dopant concentration. The main result is that the slope beta = Gamma(E >> k(B)T)/E reaches its maxima near optimal doping and scales with the superconducting transition temperature. This supports the spin fluctuation model for superconductivity for these materials. In the optimally hole-doped compound, the slope of the scattering rate of the inner hole pocket is about three times bigger than the Planckian limit Gamma(E)/E approximate to 1. This result, together with the energy dependence of the renormalization function Z(E), signals very incoherent charge carriers in the normal state which transform at low temperatures to a coherent unconventional superconducting state.