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Formation of Two‐Dimensional Copper Selenide on Cu(111) at Very Low Selenium Coverage
Author(s) -
Walen Holly,
Liu DaJiang,
Oh Junepyo,
Yang Hyun Jin,
Kim Yousoo,
Thiel Patricia A.
Publication year - 2016
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201600207
Subject(s) - scanning tunneling microscope , monolayer , density functional theory , lattice constant , copper , selenide , chemistry , lattice (music) , crystallography , adsorption , selenium , chemical physics , molecular physics , materials science , computational chemistry , diffraction , nanotechnology , physics , optics , biochemistry , organic chemistry , acoustics
Using scanning tunneling microscopy (STM), we observed that adsorption of Se on Cu(111) produced islands with a (√3×√3)R30° structure at Se coverages far below the structure's ideal coverage of 1/3 monolayer. On the basis of density functional theory (DFT), these islands cannot form due to attractive interactions between chemisorbed Se atoms. DFT showed that incorporating Cu atoms into the √3‐Se lattice stabilizes the structure, which provided a plausible explanation for the experimental observations. STM revealed three types of √3 textures. We assigned two of these as two‐dimensional layers of strained CuSe, analogous to dense planes of bulk klockmannite (CuSe). Klockmannite has a bulk lattice constant that is 11 % shorter than √3 times the surface lattice constant of Cu(111). This offers a rationale for the differences observed between these textures, for which strain limits the island size or distorts the √3 lattice. STM showed that existing step edges adsorb Se and facet toward ⟨1 2 ‾ 1⟩, which is consistent with DFT.