Density-Functional-Theory Calculations of Formation Energy of the Nitrogen-Doped Diamond

Abstract

The geometry optimization of the nitrogen-doped diamond has been carried out by the density functional theory (DFT) calculations. We model the defective diamond of substitutional and interstitial nitrogen atoms by using a simple-cubic supercell. Atoms in the supercell are relaxed by allowing them to move so that the atomic forces are less than 5.0 × 10-3 eV/Å. We calculate the formation energy for substitutional and interstitial sites. We find that the formation energy for the substitutional defect is10.89 eV. We check the convergence of the calculation with respect to the k×k×k - Monkhorst-Pack grids. We show that the energy difference between k = 4 and 6 is very small (7.0 meV). We also check the calculations by using a 216-sites supercell and find that the energy difference is 0.10 eV. Thus, the calculations of the formation energy converge well. As for the interstitial defect, we model some possible configurations and find that the smallest formation energy is 21.88 eV. Therefore, the most stable configuration of the nitrogen-doped diamond belongs to the substitutional site.

Ab initio insights into the interaction mechanisms between boron, nitrogen and oxygen doped diamond surfaces and water molecules

“…In each supercell, one dopant atom was located at a substitutional lattice site in the outer layers. While B [53] and N [54,55] atoms are known from previous studies to favour substitutional sites, it is not clear whether this is also the case for O atoms. IR absorption spectra of O-containing DLC films often indicate the presence of carbonyl oxygens [20] (C=O), but other studies found O incorporation in bridge positions (two C-O bonds) to be more stable [46], or have suggested the presence of epoxy groups [6,50].…”

Structural, Energetic, and Electronic Properties of H-Interstitial in C-Monovacancy: A First-Principles Density Functional Theory

“…Moreover, the defect volume is calculated before modification/pure diamond (𝑉 0 ) and after modification by carbon-vacancy-hydrogen (𝑉 𝑓 ). The volume changes before and after relaxation (∆𝑉) is calculated by the following equation [34]: We also calculate the formation energies for each defect structure by using equations as follows [26]:…”

Adsorption of Toxic Heavy Metal Methylmercury (MeHg) on Germanene in Aqueous Environment: A First-Principles Study

“…We then calculate the formation energy Eform and charge transfer. The Eform is defined by using the following equation [27][28][29][30][31]:…”