Abstract:
:The atomic buckling in 2D "Xenes" (such as silicene) fosters a plethora of exotic electronic properties such as a quantum spin Hall effect and could be engineered by external strain. Quantifying the buckling magnitude with subangstrom precision is, however, challenging, since epitaxially grown 2D layers exhibit complex restructurings coexisting on the surface. Here, we characterize using low-temperature (5 K) atomic force microscopy (AFM) with CO-terminated tips assisted by density functional theory (DFT) the structure and local symmetry of each prototypical silicene phase on Ag(111) as well as extended defects. Using force spectroscopy, we directly quantify the atomic buckling of these phases within 0.1-Å precision, obtaining corrugations in the 0.8- to 1.1-Å range. The derived band structures further confirm the absence of Dirac cones in any of the silicene phases due to the strong Ag-Si hybridization. Our method paves the way for future atomic-scale analysis of the interplay between structural and electronic properties in other emerging 2D Xenes.
journal_name
Proc Natl Acad Sci U S Aauthors
Pawlak R,Drechsel C,D'Astolfo P,Kisiel M,Meyer E,Cerda JIdoi
10.1073/pnas.1913489117subject
Has Abstractpub_date
2020-01-07 00:00:00pages
228-237issue
1eissn
0027-8424issn
1091-6490pii
1913489117journal_volume
117pub_type
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