Takeda Hikaru, Imai Takashi, Tachibana Makoto, Gaudet Jonathan, Gaulin Bruce D, Saparov Bayrammurad I, Sefat Athena S
Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S4M1, Canada and Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S4M1, Canada and Canadian Institute for Advanced Research, Toronto, Ontario M5G1Z8, Canada.
Phys Rev Lett. 2014 Sep 12;113(11):117001. doi: 10.1103/PhysRevLett.113.117001. Epub 2014 Sep 9.
We take advantage of the site-selective nature of the ^{75}As and ^{63}Cu NMR techniques to probe the Cu substitution effects on the local magnetic properties of the FeAs planes in Ba(Fe_{1-x}Cu_{x}){2}As{2}. We show that the suppression of antiferromagnetic Fe spin fluctuations induced by Cu substitution is weaker than a naive expectation based on a simple rigid band picture, in which each Cu atom would donate three electrons to the FeAs planes. Comparison between ^{63}Cu and ^{75}As NMR data indicates that spin fluctuations are suppressed at the Cu and their neighboring Fe sites in the tetragonal phase, suggesting the strongly local nature of the Cu substitution effects. We attribute the absence of a large superconducting dome in the phase diagram of Ba(Fe_{1-x}Cu_{x}){2}As{2} to the emergence of a nearly magnetically ordered FeAs plane under the presence of orthorhombic distortion.
我们利用(^{75}As)和(^{63}Cu)核磁共振技术的位点选择性，来探究铜替代对(Ba(Fe_{1 - x}Cu_{x}){2}As{2})中(FeAs)平面局部磁性质的影响。我们发现，由铜替代引起的反铁磁铁自旋涨落的抑制作用，比基于简单刚性带模型的天真预期要弱，在该模型中每个铜原子会向(FeAs)平面贡献三个电子。(^{63}Cu)和(^{75}As)核磁共振数据的比较表明，在四方相中，自旋涨落在铜及其相邻的铁位点处受到抑制，这表明铜替代效应具有很强的局域性。我们将(Ba(Fe_{1 - x}Cu_{x}){2}As{2})相图中不存在大的超导穹顶归因于在正交畸变存在下出现了近乎磁有序的(FeAs)平面。
