Self-consistent Vertex Correction Analysis for Iron-based Superconductors: Mechanism of Coulomb Interaction-Driven Orbital Fluctuations
Self-consistent Vertex Correction Analysis for Iron-based Superconductors: Mechanism of Coulomb Interaction-Driven Orbital Fluctuations
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DOI：
10.1103/physrevlett.109.137001
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发表时间：
2012-09-25
影响因子：
8.6
通讯作者：
Kontani, Hiroshi
中科院分区：
文献类型：
--
作者：
Onari, Seiichiro;Kontani, Hiroshi
我们研究了铁基超导体中由于多轨道库仑相互作用引起的轨道或自旋涨落的机制，超越了随机相位近似。为此，我们开发了一种自洽顶点校正（VC）方法，并发现自洽顶点校正所描述的“多模干涉效应”除了自旋涨落外，多个轨道涨落是相互强调的。然后，在J/U近似于0.1时，反铁轨道和铁轨道（=向列）涨落同时发生，两者都有助于s波超导性。特别是铁轨道波动导致了正交结构的转变以及剪切模量C-66的软化。
We study the mechanism of orbital or spin fluctuations due to multiorbital Coulomb interaction in iron-based superconductors, going beyond the random-phase approximation. For this purpose, we develop a self-consistent vertex correction (VC) method, and find that multiple orbital fluctuations in addition to spin fluctuations are mutually emphasized by the "multimode interference effect'' described by the VC. Then, both antiferro-orbital and ferro-orbital (= nematic) fluctuations simultaneously develop for J/U similar to 0.1, both of which contribute to the s-wave superconductivity. Especially, the ferro-orbital fluctuations give the orthorhombic structure transition as well as the softening of shear modulus C-66.