Electronic Band Structures of Molybdenum and Tungsten Dichalcogenides by the GW Approach

• Published in: Journal of physical chemistry. C Vol. 116; no. 14; pp. 7664 - 7671
• Main Author: Jiang, Hong
• Format: Journal Article
• Language: English
• Published: Columbus, OH American Chemical Society 12.04.2012
• Subjects: Chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Exact sciences and technology; General and physical chemistry; General, apparatus; Methods of electronic structure calculations; Physics; Surface physical chemistry; Photoelectron spectra; Band structure; Many body theory; Density of states; Electronic properties; Catalysts; Photocatalysis; Two dimensional structure; Theoretical study; Random phase approximation; Nanostructures; Molybdenum; Physical properties; Quasiparticles; Energy gap; Electronic structure; Redox reactions; Tungsten; Hafnium; Density functional method; Redox potential; Chemical properties; Green's function methods
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp300079d

Molybdenum and tungsten dichalcogenides, MX2 (M = Mo and W; X = S and Se), characterized by their quasi-two-dimensional layered structure, have attracted intensive interest due to their intriguing physical and chemical properties. In this work, quasi-particle electronic properties of these materials are investigated by many-body perturbation theory in the GW approximation, currently the most accurate first-principles approach for electronic band structure of extended systems. It is found that the fundamental band gaps of all of these materials can be well described by the GW approach, and the calculated density of states from GW quasi-particle band energies agree very well with photoemission spectroscopy data. Ionization potentials of these materials are also studied by combining the slab model using density functional theory and GW correction. On the basis of our theoretical findings, we predict that none of the materials in MX2 (M = Zr, Hf, Mo, and W; X = S and Se) in their bulk form can be directly used as the photocatalyst for overall photosplitting of water because their VBM and CBM energies do not match the redox potentials of water oxidation and reduction, which, however, can be changed by forming nanostructures, especially for MoS2.