1. Sublattice Dichotomy in Monolayer FeSe Superconductor
- Author
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Ding, Cui, Xu, Zhipeng, Jiao, Xiaotong, Hu, Qiyin, Zhao, Wenxuan, Yang, Lexian, Jiang, Kun, Jia, Jin-Feng, Wang, Lili, Hu, Jiangping, and Xue, Qi-Kun
- Subjects
Condensed Matter - Superconductivity ,Condensed Matter - Materials Science ,Condensed Matter - Strongly Correlated Electrons - Abstract
The pairing mechanism behind the monolayer FeSe is one essential question for iron-based superconductors. In this work, we show the sublattice degree of freedoms of monolayer FeSe plays a special role in its pairing properties, namely the sublattice dichotomy. The high-quality monolayer FeSe samples with atomic flat $1\times1$ topography on the SrTiO$_3$(001) substrates are grown by molecular beam epitaxy. By comparing the tunneling spectra at $\alpha$ and $\beta$ Fe sublattices, we find the coherence peak of $\alpha$-Fe at the inner gap $+V_i$ is higher than $\beta$-Fe while the coherence peak of $\beta$-Fe at $-V_i$ is higher than $\alpha$-Fe with a similar amount. We also observed a reversed effect at the outer gap $\pm V_o$. We propose the $\eta$-pairing mechanism between $k$ and $-k+Q$ is the key mechanism for this unconventional sublattice dichotomy effect., Comment: 6 pages, 4 figures
- Published
- 2024