铁基超导体三轨道Hubbard模型中超导性与轨道选择性的相互交织
Intertwined superconductivity and orbital selectivity in a three-orbital Hubbard model for the iron pnictides
AI总结：
本研究通过变分波函数研究铁基超导体三轨道Hubbard-Kanamori模型，发现强耦合下轨道自发分化形成向列型轨道选择态，且长程配对关联出现在高占据轨道，揭示了轨道选择关联、向列性与超导性的关联依赖于Hund耦合。
摘要：
我们采用显式包含空间关联和电子配对的变分波函数，研究了一种与铁基超导体相关的三轨道Hubbard-Kanamori模型。我们遍历了从填充数$n=4$（对应未掺杂铁基超导体的典型填充）到$n=3$的非磁区间，在$n=3$处发现了每个轨道均处于半填充的Mott绝缘态。在强耦合区域，当电子密度升高时，我们发现$d_{xz}$与$d_{yz}$轨道的占据数会自发分化，形成具有向列特征的轨道选择态，且该特征随密度升高而增强。其中一个轨道在所有密度下均保持半填充，另一个轨道则与$d_{xy}$轨道共同承载多余的电子密度。最重要的是，在该区域中，长程配对关联出现在占据数最大的轨道上。我们的结果凸显了轨道选择关联、向列性与超导性之间的紧密联系，这种联系需要显著的Hund耦合存在才能成立。
英文摘要：
We study a three-orbital Hubbard-Kanamori model relevant for iron-based superconductors using variational wave functions explicitly including spatial correlations and electron pairing. We span the nonmagnetic sector from filling $n=4$, which is representative of undoped iron-based superconductors, to $n=3$, where a Mott insulating state with each orbital at half filling is found. In the strong-coupling regime, when the electron density is increased, we find a spontaneous differentiation between the occupation of $d_{xz}$ and $d_{yz}$ orbitals, leading to an orbital-selective state with a nematic character that becomes stronger at increasing density. One of these orbitals stays half-filled for all densities while the other one hosts (together with the $d_{xy}$ orbital) the excess of electron density. Most importantly, in this regime long-range pairing correlations appear in the orbital with the largest occupation. Our results highlight a strong link between orbital-selective correlations, nematicity, and superconductivity, which requires the presence of a significant Hund's coupling.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
