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

Abstract

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.

First-Principle Studies of the Structural, Electronic, and Optical Properties of Double-Walled Carbon Boron Nitride Nanostructures Heterosystem under Various Interwall Distances

“…Te band gap obtained here is 3.30 eV under KS-DFT while 3.1 eV was obtained for the same structure with G 0 W 0 quasi- particle corrections which is blue-shifted. Tis result is consistent with the characteristics of G 0 W 0 calculations, i.e., yielding small band gaps [17]. Te corresponding density of states is presented in Figure 6 At the equilibrium gamma points, no bands are seen crossing the Fermi level or intersections at the Dirac point as such all the structures can be regarded as semiconductors [18].…”

Tuning the potentials of aluminum phosphide nanotube photocatalyst for wastewater treatment through band gap engineering: a DFT study

“…To cut computational cost, the k_sampling of the Brillouin zone was set at 1 × 1 × 20 while the kinetic energy cut-off was set as 60 Ry [25]. Doping was performed with boron (B) atoms which replaced some of the aluminum (Al) atoms in concentrations of 3.6% and 7.1%.…”

DFT Studies of the Photocatalytic Properties of MoS2-Doped Boron Nitride Nanotubes for Hydrogen Production

“…The complex dielectric function ε(ω) was used to determine the optical response of the hybrid SWBNNT via the Bethe-Salpeter Equation (BSE) approach. The value of ε(ω) is calculated using the equation ε ( ω ) = ε 1 ( ω ) + ε 2 ( ω ) where ε 1 (ω) is the real part and ε 2 (ω) is the imaginary part of the optical dielectric constant obtained by the Kramers–Kronig relations ε 2 ( ω ) = 1 + 2 π P ∫ ∞ 0 ω ′ ϵ 2 ( ω ) false( ω ′ 2 − ω 2 false) normald ω ′ …”

“…The complex dielectric function ε(ω) was used to determine the optical response of the hybrid SWBNNT via the Bethe-Salpeter Equation (BSE) approach. The value of ε(ω) is calculated using the equation 15 (5…”