Spin-fluctuation-mediated d+id' pairing mechanism in doped β-MNCl (M=Hf,Zr) superconductors
Spin-fluctuation-mediated d+id' pairing mechanism in doped β-MNCl (M=Hf,Zr) superconductors
复制标题
DOI：
10.1103/physrevb.81.104502
复制
发表时间：
2010-03-01
影响因子：
3.7
通讯作者：
Kuroki, Kazuhiko
中科院分区：
文献类型：
--
作者：
Kuroki, Kazuhiko
本文研究了层状氮化物β-MNCl（M=Hf，Zr）超导体的两种模型：三角晶格上的单带模型和蜂窝晶格上的双带模型。我们发现，前一个模型不足以作为一个有效的模型，而后者可以是一个很好的候选人。根据双带模型的研究，我们提出了掺杂β-MNCl中自旋涨落介导的d+id（'）波超导电性的可能性。我们表明，在掺杂的带绝缘体中获得的相对较高的T-c是蜂窝晶格上自旋涨落介导的超导性的一个特征。我们还发现费米面的差距各向异性随掺杂浓度的增加而显著增加，层间跳跃抑制了超导性。这些结果与实验结果定性一致。
We study two types of models for the superconducting layered nitride beta-MNCl (M=Hf,Zr); a single-band model on a triangular lattice, and a two-band model on a honeycomb lattice. We find that the former model does not suffice as an effective model while the latter one can be a good candidate. We propose from the study on the two-band model a possibility of spin-fluctuation-mediated d+id(')-wave superconductivity in the doped beta-MNCl. We show that the relatively high T-c obtained in the doped band insulator is a characteristic feature of the spin-fluctuation-mediated superconductivity on a honeycomb lattice. We also find that the gap anisotropy on the Fermi surface strongly increases upon increasing the doping concentration, and the interlayer hopping suppresses superconductivity. These results are in qualitative agreement with the experimental findings.