论文标题
从大量到拉伸单层FESE的磁性秩序的强烈增强，因为洪德的金属
Strong enhancement of magnetic order from bulk to stretched monolayer FeSe as Hund's metals
论文作者
论文摘要
尽管磁性在基于铁的超导体中可能与其他关键特性有关的可能性很重要，但其理解仍然远非完全是完整的，尤其是对于FESE系统。一方面，批量FESE中没有磁性顺序的起源尚待澄清。另一方面，尚不清楚Srtio $ _3 $上的单层FESE多么近，基于铁的超导体的过渡温度最高的是磁性不稳定。在这里，我们使用动力学平均场理论与密度功能理论结合使用动力学均值场理论研究了大量和单层FESE的磁性。我们发现，散装FESE中的磁性顺序与轨道间电荷波动的减少有关，这是Hund耦合的效果，并通过较大的晶体场分裂增强。同时，扩展的单层FESE中Fe原子的空间隔离导致强烈的磁性顺序，这完全被小型电子掺杂破坏。我们的工作提供了对基于铁的超导体和其他一般多轨相关系统中的磁性顺序的全面理解。
Despite of the importance of magnetism in possible relation to other key properties in iron-based superconductors, its understanding is still far from complete especially for FeSe systems. On one hand, the origin of the absence of magnetic orders in bulk FeSe is yet to be clarified. On the other hand, it is still not clear how close monolayer FeSe on SrTiO$_3$, with the highest transition temperature among iron-based superconductors, is to a magnetic instability. Here we investigate magnetic properties of bulk and monolayer FeSe using dynamical mean-field theory combined with density-functional theory. We find that suppressed magnetic order in bulk FeSe is associated with the reduction of inter-orbital charge fluctuations, an effect of Hund's coupling, enhanced by a larger crystal field splitting. Meanwhile, spatial isolation of Fe atoms in expanded monolayer FeSe leads into a strong magnetic order, which is completely destroyed by a small electron doping. Our work provides a comprehensive understanding of the magnetic order in iron-based superconductors and other general multi-orbital correlated systems as Hund's metals.
