Luo Bingcheng, Yao Yuan, Tian Enke, Song Hongzhou, Wang Xiaohui, Li Guowu, Xi Kai, Li Baiwen, Song Haifeng, Li Longtu
School of Science, China University of Geosciences, 100083 Beijing, People's Republic of China;
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing, People's Republic of China.
Proc Natl Acad Sci U S A. 2019 Aug 27;116(35):17213-17218. doi: 10.1073/pnas.1906510116. Epub 2019 Aug 12.
Two-dimensional monolayer materials, with thicknesses of up to several atoms, can be obtained from almost every layer-structured material. It is believed that the catalogs of known 2D materials are almost complete, with fewer new graphene-like materials being discovered. Here, we report 2D graphene-like monolayers from monoxides such as BeO, MgO, CaO, SrO, BaO, and rock-salt structured monochlorides such as LiCl, and NaCl using first-principle calculations. Two-dimensional materials containing -orbital atoms such as HfO, CdO, and AgCl are predicted. Adopting the same strategy, 2D graphene-like monolayers from mononitrides such as scandium nitride (ScN) and monoselenides such as cadmium selenide (CdSe) are discovered. Stress engineering is found to help stabilize 2D monolayers, through canceling the imaginary frequency of phonon dispersion relation. These 2D monolayers show high dynamic, thermal, kinetic, and mechanic stabilities due to atomic hybridization, and electronic delocalization.
二维单层材料的厚度可达几个原子，几乎可以从每一种层状结构材料中获得。人们认为已知二维材料的种类几乎已经齐全，新发现的类石墨烯材料越来越少。在此，我们使用第一性原理计算，报道了来自氧化铍、氧化镁、氧化钙、氧化锶、氧化钡等氧化物以及氯化锂、氯化钠等岩盐结构单氯化物的二维类石墨烯单层。预测了含有如氧化铪、氧化镉和氯化银等含-轨道原子的二维材料。采用相同的策略，发现了来自氮化钪等单氮化物和硒化镉等单硒化物的二维类石墨烯单层。通过消除声子色散关系的虚频，发现应力工程有助于稳定二维单层。由于原子杂化和电子离域，这些二维单层表现出高动态、热、动力学和力学稳定性。
