Normal-state spin dynamics in the iron-pnictide superconductors BaFe2(As1-xPx)2 and Ba(Fe1-xCox)2As2 probed with NMR measurements
Normal-state spin dynamics in the iron-pnictide superconductors BaFe2(As1-xPx)2 and Ba(Fe1-xCox)2As2 probed with NMR measurements
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DOI：
10.1103/physrevb.87.174507
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发表时间：
2013-05-10
影响因子：
3.7
通讯作者：
Terashima, T.
中科院分区：
文献类型：
--
作者：
Nakai, Y.;Iye, T.;Terashima, T.
基于自洽重整化（SCR）自旋涨落理论，分析了铁化合物bfe2 (As1-xPx)(2)和Ba(Fe1-xCox)(2)As-2的核磁共振结果。核磁共振弛豫率T-1（-1）和电阻率的温度依赖性可以通过SCR模型很好地再现，其中二维反铁磁（AF）自旋波动占主导地位。从非费米液体到费米液体行为的交叉特征的成功描述强烈表明，BaFe2(As1-xPx)(2)和Ba(Fe1-xCox)(2)As-2的低洼自旋涨落具有流动的AF性质，并且两种化合物中的化学取代将这些系统的距离调整到AF量子临界点。讨论了自旋涨落与超导性的密切关系，并与其他非常规超导体，铜和重费米子超导体进行了比较。此外，我们还认为这些粒子的磁性和晶格不稳定性与轨道自由度密切相关。
The NMR results in iron pnictides BaFe2(As1-xPx)(2) and Ba(Fe1-xCox)(2)As-2 are analyzed based on the self-consistent renormalization (SCR) spin-fluctuation theory. The temperature dependence of the NMR relaxation rate T-1(-1) as well as the electrical resistivity is well reproduced by a SCR model where two-dimensional antiferromagnetic (AF) spin fluctuations are dominant. The successful description of the crossover feature from non-Fermi-liquid to Fermi-liquid behavior strongly suggests that low-lying spin fluctuations in BaFe2(As1-xPx)(2) and Ba(Fe1-xCox)(2)As-2 possess an itinerant AF nature, and that chemical substitution in the two compounds tunes the distance of these systems to an AF quantum critical point. The close relationship between spin fluctuations and superconductivity is discussed compared with the other unconventional superconductors, cuprate and heavy fermion superconductors. In addition, it is suggested that magnetism and lattice instability in these pnictides are strongly linked via orbital degrees of freedom.