论文标题
在ndfeas $ _ {1-x} $ p $ _ {x} $ o $ $ $ _ {0.9} $ _ {0.9} $ _ {0.1} $的情况下，使用$ d_ {xy} $ d_ obil targe观察带有$ d_ {xy} $轨道角色的乐队。
Observation of the bands with $d_{xy}$ orbital character near the Fermi level in NdFeAs$_{1-x}$P$_{x}$O$_{0.9}$F$_{0.1}$ using angle-resolved photoemission spectroscopy
论文作者
论文摘要
我们研究了ndfeas $ _ {1-x} $ p $ _ {x} $ o $ $ _ {0.9} $ f $ _ {0.1} $（$ x $ = 0、0.2、0.4和0.6）的频段结构。两个孔带，$α_1$ $（d_ {xz}）$和$α_3$ $（d_ {z^2}）$，在$ p $ polarized Light配置中的Brillouin Zone Center中观察到，而其他两个孔带，$α_2$（$α_2$ $ $ $ $ $ $（yz yz $）$（y yz $ act）$（d_ in obs）$（d_ in y in n y in n y n y n y yz $ sty） $ s $偏振的替代方案。观察到的$γ$频段随着$ x $的增加而向下移动，这与as/p-fe-as/p的键角变化的理论预测一致。此外，观察到少数$ d_ {xy} $轨道成分的结合能量与$α_1$频段的顶部相同，因此表明最初退化的$α_1$和$α_1$和$yα_2$（d_ {xz}}/d_ yz $ d_ y y d y y d y the d y y d y the y d y the d y y d y the the the the $α_1$和$α_1$和$ d_ {yz} $ d_ 乐队。 $α_1$ band top $ d_ {xy} $ orbital字符的能量水平的变化伴随着$ t_ {c} $ upturn $ 0.2 <x <x <0.4 $。 $ t_ {c} $随着$α_1$ band向下移动，越过费米级别的速度随着$α_1$的变化而继续增加。带有$ d_ {xy} $轨道特征的初期频带对于高$ t_ {c} $ 1111型基于铁的超导体可能是重要的成分。
We studied the band structure of NdFeAs$_{1-x}$P$_{x}$O$_{0.9}$F$_{0.1}$ ($x$ = 0, 0.2, 0.4 and 0.6) using angle-resolved photoemission spectroscopy (ARPES) measurements. Two of the hole bands, $α_1$ $(d_{xz})$ and $α_3$ $(d_{z^2})$, were observed at the Brillouin zone center in the $P$-polarized light configuration, while the other two hole bands, $α_2$ $(d_{yz})$ and $γ$ $(d_{xy})$, were observed in the $S$-polarized alternative. The observed $γ$ band shifts downwards as $x$ increases, which is consistent with the theoretical prediction for the change in bond angle of As/P-Fe-As/P. Furthermore, a small amount of the $d_{xy}$ orbital component was observed at the same binding energy as that of the top of the $α_1$ band, thus indicating the band reconstruction of the originally degenerate $α_1$ and $α_2$ $(d_{xz}/d_{yz})$ bands by the unoccupied $d_{xy}$ band. The change in the energy level of the $α_1$ band top with $d_{xy}$ orbital character is accompanied by a $T_{c}$ upturn at $0.2 < x < 0.4$. The $T_{c}$ continues to increase as the $α_1$ band shifts downward, crossing the Fermi level. The incipient band with the $d_{xy}$ orbital character on its top could be an important ingredient for high $T_{c}$ 1111-type iron-based superconductors.
