Universal understanding of nematicity and magnetism in Fe-pnictides and FeSe
Universal understanding of nematicity and magnetism in Fe-pnictides and FeSe
复制标题
对铁磷族元素和 FeSe 中向列性和磁性的普遍理解
DOI：
10.1088/1361-648x/aaf404
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Lin Haiqing
中科院分区：
文献类型：
--
作者：
Zheng Xiaojun;Huang Zhongbing;Li Huan;Yang Fan;Lin Haiqing
本文采用平均场和变分蒙特卡罗方法，基于实际的五轨道Hubbard模型研究了铁基超导体（FeSCs），该模型明确地包含了场外库仑相互作用。我们的研究结果表明，在稳定fe - pnicides和FeSe的向列态中起着重要的作用。在一个临界值以下，模型处于条纹反铁磁基态，并且增加导致不同磁构型之间的能量简并。这一发现为相对较小的fe - nicides的磁性提供了一个自然的解释，更重要的是，揭示了较大的fe - nicides中磁性缺失的微观机制。同时，在不同的磁构型中，相同的各向异性和轨道占位解释了在Fe-pnictides和FeSe中观察到的相似的轨道顺序。此外，当考虑到对能带结构的重整化效应时，FeSe中费米表面的异常小。
By employing the mean field and variational Monte Carlo methods, we investigate the iron-based superconductors (FeSCs) based on a realistic five-orbital Hubbard model in which an off-site Coulomb interaction is explicitly included. Our results demonstrate that plays an important role in stabilizing the nematic state in both Fe-pnictides and FeSe. Below a critical , the model is shown to lie in the striped antiferromagnetic ground state, and an increasing of leads to an energy degeneracy between different magnetic configurations. This finding provides a natural explanation for the magnetism in Fe-pnictides with relatively small , and more importantly, unveils the microscopic mechanism behind the absence of magnetic order in FeSe with larger . Simultaneously, the common anisotropy of and orbital occupations in different magnetic configurations accounts for the similar orbital ordering observed in Fe-pnictides and FeSe. In addition, the unusual smallness of the Fermi surfaces in FeSe can be obtained when the renormalization effect of on the band structure is taken into account.