title: Experimental realization of two-dimensional boron sheets.
abstract: A variety of two-dimensional materials have been reported in recent years, yet single-element systems such as graphene and black phosphorus have remained rare. Boron analogues have been predicted, as boron atoms possess a short covalent radius and the flexibility to adopt sp(2) hybridization, features that favour the formation of two-dimensional allotropes, and one example of such a borophene material has been reported recently. Here, we present a parallel experimental work showing that two-dimensional boron sheets can be grown epitaxially on a Ag(111) substrate. Two types of boron sheet, a β12 sheet and a χ3 sheet, both exhibiting a triangular lattice but with different arrangements of periodic holes, are observed by scanning tunnelling microscopy. Density functional theory simulations agree well with experiments, and indicate that both sheets are planar without obvious vertical undulations. The boron sheets are quite inert to oxidization and interact only weakly with their substrate. We envisage that such boron sheets may find applications in electronic devices in the future.
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Baojie
authors.initials: B
authors.lastname: Feng
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhong
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Li
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Li
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Cheng
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Meng
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Chen
authors.affiliation: Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.|Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
authors.forename: Kehui
authors.initials: K
authors.lastname: Wu