1. Topological Fermi-arc surface state covered by floating electrons on a two-dimensional electride
- Author
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Lim, Chan-young, Kim, Min-Seok, Lim, Dong Cheol, Kim, Sunghun, Lee, Yeonghoon, Cha, Jaehoon, Lee, Gyubin, Song, Sang Yong, Thapa, Dinesh, Denlinger, Jonathan D., Kim, Seong-Gon, Kim, Sung Wng, Seo, Jungpil, and Kim, Yeongkwan
- Subjects
Condensed Matter - Materials Science - Abstract
Two-dimensional electrides can acquire topologically non-trivial phases due to intriguing interplay between the cationic atomic layers and anionic electron layers. However, experimental evidence of topological surface states has yet to be verified. Here, via angle-resolved photoemission spectroscopy (ARPES) and scanning tunnelling microscopy (STM), we probe the magnetic Weyl states of the ferromagnetic electride $[Gd_{2}$C]^{2+}\cdot2e^{-}$. In particular, the presence of Weyl cones and Fermi-arc states is demonstrated through photon energy-dependent ARPES measurements, agreeing with theoretical band structure calculations. Notably, the STM measurements reveal that the Fermi-arc states exist underneath a floating quantum electron liquid on the top Gd layer, forming double-stacked surface states in a heterostructure. Our work thus not only unveils the non-trivial topology of the $[Gd_{2}$C]^{2+}\cdot2e^{-}$ electride but also realizes a surface heterostructure that can host phenomena distinct from the bulk., Comment: 22 pages, 6 figures
- Published
- 2024
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