TY - JOUR
T1 - Geometric imaging of borophene polymorphs with functionalized probes
AU - Liu, Xiaolong
AU - Wang, Luqing
AU - Li, Shaowei
AU - Rahn, Matthew S.
AU - Yakobson, Boris I.
AU - Hersam, Mark C.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - A 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 v 1/5 and v 1/6 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.
AB - A 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 v 1/5 and v 1/6 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.
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U2 - 10.1038/s41467-019-09686-w
DO - 10.1038/s41467-019-09686-w
M3 - Article
C2 - 30967559
AN - SCOPUS:85064047754
VL - 10
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 1642
ER -