Orbital Origin of Extremely Anisotropic Superconducting Gap in Nematic Phase of FeSe Superconductor
Autor: | Bing Shen, Shenjin Zhang, Zhimin Wang, Qiang Gao, B. Lei, Jiangping Hu, Xu Liu, Defa Liu, Jianwei Huang, Chuangtian Chen, Zuyan Xu, Tao Xiang, Lin Zhao, Ping Ai, Youguo Shi, Yiyuan Mao, Aiji Liang, Xianxin Wu, Yong Hu, Li Yu, Xingjiang Zhou, Yu Xu, Shaolong He, Jing Liu, Xiaoli Dong, Xiaowen Jia, Guodong Liu, Qinjun Peng, Feng Yang, Y. H. Zhang, Cong Li, Xianhui Chen, Le Wang, Fengfeng Zhang |
---|---|
Jazyk: | angličtina |
Rok vydání: | 2018 |
Předmět: |
Superconductivity
Physics Condensed matter physics Condensed Matter - Superconductivity QC1-999 Fermi level General Physics and Astronomy FOS: Physical sciences Fermi surface 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Mott transition Brillouin zone Superconductivity (cond-mat.supr-con) symbols.namesake Atomic orbital Condensed Matter::Superconductivity 0103 physical sciences symbols 010306 general physics 0210 nano-technology Anisotropy Spin (physics) |
Zdroj: | Physical Review X, Vol 8, Iss 3, p 031033 (2018) Physical Review X |
ISSN: | 2160-3308 |
Popis: | The iron-based superconductors are characterized by multiple-orbital physics where all the five Fe 3$d$ orbitals get involved. The multiple-orbital nature gives rise to various novel phenomena like orbital-selective Mott transition, nematicity and orbital fluctuation that provide a new route for realizing superconductivity. The complexity of multiple-orbital also asks to disentangle the relationship between orbital, spin and nematicity, and to identify dominant orbital ingredients that dictate superconductivity. The bulk FeSe superconductor provides an ideal platform to address these issues because of its simple crystal structure and unique coexistence of superconductivity and nematicity. However, the orbital nature of the low energy electronic excitations and its relation to the superconducting gap remain controversial. Here we report direct observation of highly anisotropic Fermi surface and extremely anisotropic superconducting gap in the nematic state of FeSe superconductor by high resolution laser-based angle-resolved photoemission measurements. We find that the low energy excitations of the entire hole pocket at the Brillouin zone center are dominated by the single $d_{xz}$ orbital. The superconducting gap exhibits an anti-correlation relation with the $d_{xz}$ spectral weight near the Fermi level, i.e., the gap size minimum (maximum) corresponds to the maximum (minimum) of the $d_{xz}$ spectral weight along the Fermi surface. These observations provide new insights in understanding the orbital origin of the extremely anisotropic superconducting gap in FeSe superconductor and the relation between nematicity and superconductivity in the iron-based superconductors. 19 pages, 4 figures |
Databáze: | OpenAIRE |
Externí odkaz: |