Unique crystal field splitting and multiband RKKY interactions in Ni-doped EuRbFe4As4
Unique crystal field splitting and multiband RKKY interactions in Ni-doped EuRbFe4As4
复制标题
Ni 掺杂 EuRbFe4As4 中独特的晶体场分裂和多带 RKKY 相互作用
DOI：
10.1038/s42005-019-0112-1
复制
发表时间：
2019
影响因子：
5.5
通讯作者：
Chao Cao
中科院分区：
文献类型：
--
作者：
Chenchao Xu;Qijin Chen;Chao Cao
磁性与超导性之间的关系一直是铁基超导体中讨论最多的话题之一。利用第一性原理计算，研究了1144型铁基超导体eubfe4as4的电子结构。我们发现eurbfe4as4的晶体场分裂是独特的，因此其轨道比其轨道更接近费米能级。在原始的EuRbFe4As4中Ruderman - Kittel - Kasuya - Yosida （RKKY）相互作用强度约为0.12 meV。在Fe位点上掺杂ni后，由于费米表面的高度各向异性和多带效应，RKKY相互作用强度几乎没有变化，尽管态的dzx(y)密度急剧降低。最后，在原始和掺杂的化合物中，RKKY相互作用主要是通过铁轨道的能带介导的。我们的计算表明RKKY相互作用介导的比轨轨道可能是导致eurbfe4as4磁性的原因，并且在ni掺杂后不会改变。
The relationship between magnetism and superconductivity has been one of the most discussed topics in iron-based superconductors. Using first-principles calculations, we have studied the electronic structure of 1144-type iron-based superconductor EuRbFe4As4. We find the crystal field splitting of EuRbFe4As4is unique, such that theorbitals are closer to the Fermi levelthan thedxyorbitals. The Ruderman−Kittel−Kasuya−Yosida (RKKY) interaction strength is approximately 0.12 meV in pristine EuRbFe4As4. Upon Ni-doping on the Fe site, the RKKY interaction strength is barely changed upon Ni-doping due to the highly anisotropic Fermi surfaces and multiband effect, despite the drastically reduceddzx(y)density of state at. Finally, in both pristine and doped compounds, the RKKY interaction is primarily mediated through bands due to Fe-orbitals. Our calculations suggest the RKKY interaction mediated byorbital is probably responsible for the magnetism in EuRbFe4As4and doesn’t change upon Ni-doping.