Growth and Electronic Structure of Copper Oxide Monolayer Epitaxial Films

Youngdo Kim; Byeongjun Gil; Jinkwon Kim; Yeonjae Lee; Donghan Kim; Sungsoo Hahn; Tae Won Noh; Miyoung Kim; Changyoung Kim

doi:10.1021/acs.nanolett.3c00994

Growth and Electronic Structure of Copper Oxide Monolayer Epitaxial Films

Nano Lett. 2023 Aug 23;23(16):7273-7278. doi: 10.1021/acs.nanolett.3c00994. Epub 2023 Aug 8.

Authors

Youngdo Kim^{1

2}, Byeongjun Gil³, Jinkwon Kim^{1

2}, Yeonjae Lee^{1

2}, Donghan Kim^{1

2}, Sungsoo Hahn^{2

4}, Tae Won Noh^{1

2}, Miyoung Kim³, Changyoung Kim^{1

2}

Affiliations

¹ Center for Correlated Electron Systems, Institute for Basic Science, Seoul 08826, Korea.
² Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea.
³ Department of Materials Science and Engineering and Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Korea.
⁴ Research Institute of Basic Sciences (RIBS), Seoul National University, Seoul 08826, Korea.

PMID: 37552567
DOI: 10.1021/acs.nanolett.3c00994

Abstract

Copper-based high-temperature superconductors share a common feature in their crystal structure, which is the presence of a CuO₂ plane, where superconductivity takes place. Therefore, important questions arise as to whether superconductivity can exist in a single layer of the CuO₂ plane and, if so, how such superconductivity in a single CuO₂ plane differs from that in a bulk cuprate system. To answer these questions, studies of the superconductivity in cuprate monolayers are necessary. In this study, we constructed a heterostructure system with a La_2-xSr_xCuO₄ (LSCO) monolayer containing a single CuO₂ plane and measured the resulting electronic structures. Monolayer LSCO has metallic and bulk-like electronic structures. The hole doping ratio of the monolayer LSCO is found to depend on the underlying buffer layer due to the interface effect. Our work will provide a platform for research into ideal two-dimensional cuprate systems.

Keywords: CuO2 monolayer; La2−xSrxCuO4; angle-resolved photoemission spectroscopy; cuprate thin film; electronic structure; pulsed laser deposition.