论文标题

表面$ s $ - 氧化物终止的无限层镍的超导率

Surface $s$-wave superconductivity for oxide-terminated infinite-layer nickelates

论文作者

Wu, Xianxin, Jiang, Kun, Di Sante, Domenico, Hanke, Werner, Schnyder, A. P., Hu, Jiangping, Thomale, Ronny

论文摘要

我们分析了无限层镍的不同表面终止的电子结构。与平面散装层相比,Surface Nio $ _2 $层是弯曲的。虽然稀有地面终止表面费米学类似于镍的大容量极限,但NIO $ _2 $终止的表面带结构发生了显着改变,这是由于缺乏稀土原子对晶体场裂解的影响。与散装的费米表面相反,有两个Ni-$ 3d $ fermi口袋,从而在$ \ bar {\ text {m}} $ point a Surface Brillouin区域中产生了增强的光谱重量。从强耦合分析中,我们获得了地表层的主要扩展$ S $波超导性,而不是批量的$ d $波。这一发现将镍与等值粉碎物区分开来,在同类表面配对机构中不太明显。我们的结果与最近的STM测量中揭示的区域依赖性间隙结构一致,并提供了一个ANSATZ来解释无限层镍盐表面敏感测量的实验数据。

We analyze the electronic structure of different surface terminations for infinite-layer nickelates. Surface NiO$_2$ layers are found to be buckled, in contrast to planar bulk layers. While the rare-earth terminated surface fermiology is similar to the bulk limit of the nickelates, the NiO$_2$ terminated surface band structure is significantly altered, originating from the effect of absence of rare-earth atoms on the crystal field splitting. Contrary to the bulk Fermi surfaces, there are two Ni-$3d$ Fermi pockets, giving rise to enhanced spectral weight around the $\bar{\text{M}}$ point in the surface Brillouin zone. From a strong-coupling analysis, we obtain dominant extended $s$-wave superconductivity for the surface layer, as opposed to $d$-wave for the bulk. This finding distinguishes the nickelates from isostructural cuprates, where the analogous surface pairing mechanism is less pronounced. Our results are consistent with region-dependent gap structures revealed in recent STM measurements and provide an ansatz to interpret experimental data of surface-sensitive measurements on the infinite-layer nickelates.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源