Orbital-selective two-dimensional superconductivity in 2H-NbS2
Orbital-selective two-dimensional superconductivity in 2H-NbS2
复制标题
2H·NbS2 中的轨道选择性二维超导
DOI：
10.1103/physrevresearch.4.013188
复制
发表时间：
2022-03-08
影响因子：
4.2
通讯作者：
Yuan, Hongtao
中科院分区：
文献类型：
--
作者：
Bi, Xiangyu;Li, Zeya;Yuan, Hongtao
轨道选择超导性对于理解多带超导体的配对机制至关重要。具有各向异性空间扩展的原子d轨道可以直接决定能带结构中具有二维或三维性质的子带的能量色散。理论上，由于这些2D和3D子带的共存，轨道选择超导性可以在多带超导体中表现出带相关的维数。然而，要在实验上证实这种轨道选择性的2D超导性仍然具有挑战性和难以捉摸。在2 H-NbS_2厚片上，基于角度相关的上临界磁场，我们观察到Nb原子d（xy）和d（x）（2）-（2）（y）轨道上的一个与二维超导子带相关的尖形峰和一个与三维超导子带相关的圆峰，直接证实了2 H-NbS_2厚片中本征二维超导性的存在及其轨道选择性超导性质。二维超导性在大电流或高压下仍然保持稳定。这些观测结果揭示了轨道选择性配对机制和由此产生的多带超导体的带依赖维数。
Orbital-selective superconductivity is crucial for understanding the pairing mechanism for multiband superconductors. Atomic d orbitals with anisotropic spatial extension can directly determine the energy dispersion of subbands with two-dimensional (2D) or three-dimensional (3D) nature in band structure. Theoretically, owing to the coexistence of these 2D and 3D subbands, the orbital-selective superconductivity can exhibit band-dependent dimensionality in multiband superconductors. However, to experimentally confirm this orbital-selective 2D superconductivity remains challenging and elusive. Herein, based on angle-dependent upper critical magnetic field on 2H-NbS2 flakes, we observe a cusp peak associated with a 2D superconducting subband from the d(xy) and d(x)(2)-(2)(y) orbitals of Nb atoms, and a round peak related to a 3D subband, directly confirming the existence of intrinsic 2D superconductivity in 2H-NbS2 thick flake and its orbital-selective superconducting nature. The 2D superconductivity remains robust under large electric current or high pressure. Such observations shed light on the orbital-selective pairing mechanism and resulting band-dependent dimensionality for multiband superconductors.