Effects of strain on the electronic and optical properties of MgO (111) nanosheet

Effect of Oxygen Vacancy Defects on Electronic and Optical Properties of $MgO$ Monolayers: First Principles Study

“…The threshold energy values of imaginary dielectric function of the considered monolayers (Table 2) signify the optical gap [23]. The optical gap for polarization is slightly lower than that of E z polarization, which agrees well with previous theoretical results [23]. The optical gap values of the MgO monolayers are in consistent with the computed electronic band gap values discussed in section 3.2.…”

“…Several types of electronic transitions may be responsible for these low energy peaks, such asfrom the VBM (O (2p)) to defect levels, from defect levels to CBM (Mg (3s)) and in between the defect levels as seen in the DOS plots. The threshold energy values of imaginary dielectric function of the considered monolayers (Table 2) signify the optical gap [23]. The optical gap for polarization is slightly lower than that of E z polarization, which agrees well with previous theoretical results [23].…”

“…The values of static dielectric constant ( r (0)), the dielectric constant at zero frequency limit (Figures 4(a) and 4(b)) for P for both (E x) and (E z) match well with a those of a recent report [24]. The pristine ( r (0)) value calculated earlier at PAW level are found to be slightly greater than the HSE values [23,24]. When oxygen atom vacancies are introduced into the MgO monolayer, the ( r (0)) values increase from that of P following the trend P < V O < V 2O -II < V 2O -I for (E x) and P < V O < V 2O -II = V 2O − I for (E z).…”

“…The nmax values of V O and V 2O -I monolayers along (E x) are observed in the visible region, while they appear in the UV region for all other cases. The energies at which extinction coefficient maxima (k max ) appear signify the fastest and the strongest absorption of photons [23]. Similar to n(ω), red shift of kmax energies (Table 2) is noticed for defective systems with respect to the pristine monolayer.…”

“…Later, another DFT work has portrayed the honeycomb-like MgO ML as a potential candidate for optoelectronic applications [22]. M. Yeganeh and F. Kafi investigated the variation in optical properties of graphene like MgO (111) MLs under the application of strain [23]. N and F functionalizations are found to enhance the optical properties of MgO single layer over the pristine [24].…”