Systematic Trends in Hybrid-DFT Computations of BaTiO3/SrTiO3, PbTiO3/SrTiO3 and PbZrO3/SrZrO3 (001) Hetero Structures

Abstract

We performed predictive hybrid-DFT computations for PbTiO3, BaTiO3, SrTiO3, PbZrO3 and SrZrO3 (001) surfaces, as well as their BaTiO3/SrTiO3, PbTiO3/SrTiO3 and PbZrO3/SrZrO3 (001) heterostructures. According to our hybrid-DFT computations for BO2 and AO-terminated ABO3 solid (001) surfaces, in most cases, the upper layer ions relax inwards, whereas the second layer ions shift upwards. Our hybrid-DFT computed surface rumpling s for the BO2-terminated ABO3 perovskite (001) surfaces almost always is positive and is in a fair agreement with the available LEED and RHEED experiments. Computed B-O atom chemical bond population values in the ABO3 perovskite bulk are enhanced on its BO2-terminated (001) surfaces. Computed surface energies for BO2 and AO-terminated ABO3 perovskite (001) surfaces are comparable; thus, both (001) surface terminations may co-exist. Our computed ABO3 perovskite bulk Γ-Γ band gaps are in fair agreement with available experimental data. BO2 and AO-terminated (001) surface Γ-Γ band gaps are always reduced with regard to the respective bulk band gaps. For our computed BTO/STO and PTO/STO (001) interfaces, the average augmented upper-layer atom relaxation magnitudes increased by the number of augmented BTO or PTO (001) layers and always were stronger for TiO2-terminated than for BaO or PbO-terminated upper layers. Our B3PW concluded that BTO/STO, as well as SZO/PZO (001) interface Γ-Γ band gaps, very strongly depends on the upper augmented layer BO2 or AO-termination but considerably less so on the number of augmented (001) layers.

Review of First Principles Simulations of STO/BTO, STO/PTO, and SZO/PZO (001) Heterostructures

“…According to our ab initio B3PW computations, the largest chemical bond populations are between the Ti and O atoms (0.100e) in the BTO perovskite and between the Zr and O atoms (0.100e) in the PZO perovskite (Table 4). We carried out ab initio B3PW computations of the STO/BTO (001) heterostructures [77,91] by means of the symmetrically terminated slab model (Figure 1). The TiO2-terminated STO (001) substrate contained eleven atomic monolayers (Figure 1).…”

Two-dimensional C6X (X = P2, N2, NP) with ultra-wide bandgap and high carrier mobility

“…On the other hand, the Hartree-Fock (HF) method tends to overestimate the bandgaps. However, recent theoretical studies have suggested that by utilizing the B3LYP or B3PW functionals, it is possible to achieve excellent agreement between the calculated band gaps and experimental data for ABO 3 perovskites [37,38]. For the phonon spectra calculation, the density-functional-perturbation theory (DFPT) was used and 5 × 5 × 1 supercell of C 3 P, C 3 N and C 6 NP was adopted [39].…”

DFT insights into LaFeO3 with Mn substitution: A promising path to energy‐efficient magneto‐optical applications

“…It is reported that modified Becke and Johnson (mBJ) exchange-correlation potential and hybrid exchangecorrelation functionals such as B3LYP or B3PW have demonstrated the capability to achieve excellent agreement with experimental band gap values for ABO 3 perovskite materials. 29,30 In contrast, GGA descriptions of exchange and correlation effects often result in an underestimation of the band gap. To address this band gap underestimation, we have employed the mBJ exchange-correlation potential to enhance the accuracy of our electronic band gap calculations for the studied materials.…”

“…As for this work, one has used the generalized gradient approximation (GGA) 28 under the effects of spin polarization considering the following formula. where and are the number of electrons in spin‐down and spin‐up configuration, respectively. It is reported that modified Becke and Johnson (mBJ) exchange‐correlation potential and hybrid exchange‐correlation functionals such as B3LYP or B3PW have demonstrated the capability to achieve excellent agreement with experimental band gap values for ABO 3 perovskite materials 29,30 . In contrast, GGA descriptions of exchange and correlation effects often result in an underestimation of the band gap.…”