Title

Structure of chalcogen overlayers on Au(111): Density functional theory and lattice-gas modeling

Publication Date

6-9-2020

Department

Chemistry; Materials Science and Engineering; Ames Laboratory; Physics and Astronomy

Campus Units

Ames Laboratory, Chemistry, Materials Science and Engineering, Physics and Astronomy

OSTI ID+

1632685

Report Number

IS-J 10238

DOI

10.1063/5.0006131

Journal Title

The Journal of Chemical Physics

Volume Number

152

Issue Number

22

First Page

224706

Abstract

Ordering of different chalcogens, S, Se, and Te, on Au(111) exhibit broad similarities but also some distinct features, which must reflect subtle differences in relative values of the long-range pair and many-body lateral interactions between adatoms. We develop lattice-gas (LG) models within a cluster expansion framework, which includes about 50 interaction parameters. These LG models are developed based on density functional theory (DFT) analysis of the energetics of key adlayer configurations in combination with the Monte Carlo (MC) simulation of the LG models to identify statistically relevant adlayer motifs, i.e., model development is based entirely on theoretical considerations. The MC simulation guides additional DFT analysis and iterative model refinement. Given their complexity, development of optimal models is also aided by strategies from supervised machine learning. The model for S successfully captures ordering motifs over a broader range of coverage than achieved by previous models, and models for Se and Te capture the features of ordering, which are distinct from those for S. More specifically, the modeling for all three chalcogens successfully explains the linear adatom rows (also subtle differences between them) observed at low coverages of ∼0.1 monolayer. The model for S also leads to a new possible explanation for the experimentally observed phase with a (5 × 5)-type low energy electron diffraction (LEED) pattern at 0.28 ML and to predictions for LEED patterns that would be observed with Se and Te at this coverage.

DOE Contract Number(s)

AC02-07CH11358; AC02-05CH11231; CHE-1507223

Language

en

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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