Structural Characterization of a Novel Two-Dimensional Material: Cobalt Sulfide Sheets on Au(111)

Mahesh K Prabhu; Dajo Boden; Marcel J Rost; Jörg Meyer; Irene M N Groot

doi:10.1021/acs.jpclett.0c02268

Structural Characterization of a Novel Two-Dimensional Material: Cobalt Sulfide Sheets on Au(111)

J Phys Chem Lett. 2020 Nov 5;11(21):9038-9044. doi: 10.1021/acs.jpclett.0c02268. Epub 2020 Oct 12.

Authors

Mahesh K Prabhu¹, Dajo Boden¹, Marcel J Rost², Jörg Meyer¹, Irene M N Groot¹

Affiliations

¹ Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
² Huygens-Kamerlingh Onnes Laboratory, Leiden Institute of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands.

Abstract

Transition metal dichalcogenides (TMDCs) are a type of two-dimensional (2D) material that has been widely investigated by both experimentalists and theoreticians because of their unique properties. In the case of cobalt sulfide, density functional theory (DFT) calculations on free-standing S-Co-S sheets suggest there are no stable 2D cobalt sulfide polymorphs, whereas experimental observations clearly show TMDC-like structures on Au(111). In this study, we resolve this disagreement by using a combination of experimental techniques and DFT calculations, considering the substrate explicitly. We find a 2D CoS(0001)-like sheet on Au(111) that delivers excellent agreement between theory and experiment. Uniquely this sheet exhibits a metallic character, contrary to most TMDCs, and exists due to the stabilizing interactions with the Au(111) substrate.