Liu, XiaolongWang, LuqingLi, ShaoweiRahn, Matthew S.Yakobson, Boris I.Hersam, Mark C.2020-02-142020-02-142019Liu, Xiaolong, Wang, Luqing, Li, Shaowei, et al.. "Geometric imaging of borophene polymorphs with functionalized probes." <i>Nature Communications,</i> 10, (2019) Springer Nature: https://doi.org/10.1038/s41467-019-09686-w.https://hdl.handle.net/1911/108051A common characteristic of borophene polymorphs is the presence of hollow hexagons (HHs) in an otherwise triangular lattice. The vast number of possible HH arrangements underlies the polymorphic nature of borophene, and necessitates direct HH imaging to definitively identify its atomic structure. While borophene has been imaged with scanning tunneling microscopy using conventional metal probes, the convolution of topographic and electronic features hinders unambiguous identification of the atomic lattice. Here, we overcome these limitations by employing CO-functionalized atomic force microscopy to visualize structures corresponding to boron-boron covalent bonds. Additionally, we show that CO-functionalized scanning tunneling microscopy is an equivalent and more accessible technique for HH imaging, confirming the v1/5 and v1/6 borophene models as unifying structures for all observed phases. Using this methodology, a borophene phase diagram is assembled, including a transition from rotationally commensurate to incommensurate phases at high growth temperatures, thus corroborating the chemically discrete nature of borophene.engThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.Journal articles41467-019-09686-whttps://doi.org/10.1038/s41467-019-09686-w