Two-dimensional (2D) materials with a Lieb lattice can host exotic electronic band structures. Such a system does not exist in nature, and it is also difficult to obtain in the laboratory due to its structural instability. Here, we experimentally realized a 2D system composed of a tin overlayer on an aluminum substrate by molecular beam epitaxy. The specific arrangement of Sn atoms on the Al(100) surface, which benefits from favorable interface interactions, forms a stabilized buckled Lieb lattice. Our theoretical calculations indicate a partially broken nodal line loop protected by its mirror reflection symmetry and a topologically nontrivial insulating state with a spin-orbital coupling (SOC) effect in the band structure of this Lieb lattice. The electronic structure of this system has also been experimentally characterized by scanning tunnelling spectroscopy and angle-resolved photoemmision spectroscopy. Our work provides an appealing method for constructing 2D quantum materials based on the Lieb lattice.
@article{arxiv.2001.01045,
title = {Experimental Realization of Two-Dimensional Buckled Lieb lattice},
author = {Haifeng Feng and Chen Liu and Si Zhou and Nan Gao and Qian Gao and Jincheng Zhuang and Xun Xu and Zhenpeng Hu and Jiaou Wang and Lan Chen and Jijun Zhao and Yi Du},
journal= {arXiv preprint arXiv:2001.01045},
year = {2020}
}