Realization of a Two-Dimensional Checkerboard Lattice in Monolayer Cu<sub>2</sub>N.

Hu, Xuegao; Zhang, Run-Wu; Ma, Da-Shuai; Cai, Zhihao; Geng, Daiyu; Sun, Zhenyu; Zhao, Qiaoxiao; Gao, Jisong et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

Two-dimensional checkerboard lattice, the simplest line-graph lattice, has been intensively studied as a toy model, while material design and synthesis remain elusive. Here, we report theoretical prediction and experimental realization of the checkerboard lattice in monolayer Cu<sub>2</sub>N. Experimentally, monolayer Cu<sub>2</sub>N can be realized in the well-known N/Cu(100) and N/Cu(111) systems that were previously mistakenly believed to be insulators. Combined angle-resolved photoemission spectroscopy measurements, first-principles calculations, and tight-binding analysis show that both systems host checkerboard-derived hole pockets near the Fermi level. In addition, monolayer Cu<sub>2</sub>N has outstanding stability in air and organic solvents, which is crucial for further device applications.