1. Momentum-resolved electronic structures and strong electronic correlations in graphene-like nitride superconductors
- Author
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Bi, Jiachang, Lin, Yu, Zhang, Qinghua, Liu, Zhanfeng, Zhang, Ziyun, Zhang, Ruyi, Yao, Xiong, Chen, Guoxin, Liu, Haigang, Huang, Yaobo, Sun, Yuanhe, Zhang, Hui, Sun, Zhe, Xiao, Shaozhu, and Cao, Yanwei
- Subjects
Condensed Matter - Materials Science ,Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Superconductivity - Abstract
Although transition-metal nitrides have been widely applied for several decades, experimental investigations of their high-resolution electronic band structures are rare due to the lack of high-quality single-crystalline samples. Here, we report on the first momentum-resolved electronic band structures of titanium nitride (TiN) films, a remarkable nitride superconductor. The measurements of crystal structures and electrical transport properties confirmed the high quality of these films. More importantly, with a combination of high-resolution angle-resolved photoelectron spectroscopy and the first-principles calculations, the extracted Coulomb interaction strength of TiN films can be as large as 8.5 eV, whereas resonant photoemission spectroscopy yields a value of 6.26 eV. These large values of Coulomb interaction strength indicate that superconducting TiN is a strongly correlated system. Our results uncover the unexpected electronic correlations in transition-metal nitrides, potentially providing a perspective not only to understand their emergent quantum states but also to develop their applications in quantum devices., Comment: 11 pages, 5 figures
- Published
- 2024
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