论文标题
潜在超导体KCA $ _2 $ fe $ _4 $ AS $ _4 $ o $ _2 $中的异常金属氧带
Anomalous metallic oxygen band in the potential superconductor KCa$_2$Fe$_4$As$_4$O$_2$
论文作者
论文摘要
通过First-Principes dft/gga方法研究了一个孔自载潜在的基于铁的超导体kca $ _2 $ _4 $的电子结构，磁性和费米表面。提出了对Wannier函数基础的投影，以直接计算自兴奋剂值。特别是对于KCA $ _2 $ fe $ _4 $ as $ _4 $ o $ _2 $，在FE-3D状态下为0.75孔。出乎意料的是，对于KCA $ _2 $ fe $ _4 $，$ _4 $ o $ $ _2 $，发现除了Fe-3D频段O-2P频段外，O-2P频段也越过Fermi级别，这对于O-2P状态来说是非常异常的行为。通常，O-2P状态通常在过渡金属氧化物中完全占据。在这里，由于CAO层将某些电子提供给群层的事实并非如此，因此将O-2P状态部分占据。 O-2P状态形成额外的费米表面板，其形状像$γ$ - 点约$γ$ - 并因杂交而修改Fe-3d费米表面片。 To prove the presence of anomalous metallic O-2p band in KCa$_2$Fe$_4$As$_4$O$_2$ the comparative study with the same family systems KCa$_2$Fe$_4$As$_4$F$_2$ and RbGd$_2$Fe$_4$As$_4$O$_2$ (where it is not the case) was performed.发现磁接地状态是带有棋盘订购的抗铁磁磁性。因此，我们预计KCA $ _2 $ fe $ _4 $ as $ _4 $ o $ _2 $可能是具有不寻常属性的潜在超导体。
The electronic structure, magnetism and Fermi surface of a hole self-doped potential iron-based superconductor KCa$_2$Fe$_4$As$_4$O$_2$ (12442) were studied by a first-principes DFT/GGA approach. The projection onto Wannier functions basis is proposed to calculate directly the self-doping value. In particular for KCa$_2$Fe$_4$As$_4$O$_2$ it is 0.75 hole on Fe-3d states. Surprisingly, for the KCa$_2$Fe$_4$As$_4$O$_2$ it was found that except the Fe-3d bands the O-2p bands also cross the Fermi level, which is quite anomalous behavior for O-2p states. In general, the O-2p states are usually fully occupied in transition metal oxides. Here it is not the case due to the fact that CaO layer gives some of the electrons to the FeAs layer, thus leaving O-2p states partially occupied. The O-2p states form additional Fermi surface sheet with propeller-like shape around $Γ$-point and modify the Fe-3d Fermi surface sheets due to the hybridization. To prove the presence of anomalous metallic O-2p band in KCa$_2$Fe$_4$As$_4$O$_2$ the comparative study with the same family systems KCa$_2$Fe$_4$As$_4$F$_2$ and RbGd$_2$Fe$_4$As$_4$O$_2$ (where it is not the case) was performed. The magnetic ground state is found to be antiferromagnetic with checkerboard ordering. Therefore, we expect that the KCa$_2$Fe$_4$As$_4$O$_2$ might be a potential superconductor with unusual properties.
