Effects of Exchange Correlation Functional (Vwdf3) on the Structural, Elastic, and Electronic Properties of Transition Metal Dichalogenides

• Published in: Journal of Nigerian Society of Physical Sciences Vol. 5; no. 1; p. 1094
• Main Authors: Aminu Yamusa, Shehu, Shaari, A, Isah, Ibrahim, Bello Ibrahim, Usama, I. Kunya, Salisu, Abdulkarim, Sani, Itas, Y. S., Alsalamh, M.
• Format: Journal Article
• Language: English
• Published: Nigerian Society of Physical Sciences 14.01.2023
• Subjects: Dichalcogenides; Hexagonal; PBE; Van der Waals; vdW-DF3
• ISSN: 2714-2817; 2714-4704
• DOI: 10.46481/jnsps.2023.1094

In this research, the effects of Van der Waals forces on the structural, elastic, electronic, and optical properties of bulk transition metals dichalcogenides (TMDs) were studied using a novel exchange-correlation functional, vdW-DF3. This new functional tries to correct the hidden Van der Waals problems which are not reported by the previous exchange functionals. Molybdenum dichalcogenide, MoX 2 (X = S, Se, Te) was chosen as a representative transition metal dichalcogenide to compare the performance of the newly designed functional with the other two popular exchange-correlation functional; PBE and rVV10. From the results so far obtained, the analysis of the structural properties generally revealed better performance by vdW-DF3 via the provision of information on lattice parameters very closer to the experimental value. For example, the lattice constant obtained by vdW-DF3 was 3.161 Å which is very close to 3.163 Å and 3.160 Å experimental and theoretical values respectively. Calculations of the electronic properties revealed good performance by vdW-DF3 functional. Furthermore, new electronic features were revealed for MoX2 (X = S, Se, Te). In terms of optical properties, PBE functional demonstrates lower absorption than vdW-DF3, as such it can be reported that vdW-DF3 improves photon absorption by TMDs. However, our results also revealed that vdW-DF3 performed well for MoS2 than for MoSe2 and MoTe2 because of the lower density observed for the S atom in MoS2.