这项工作采用密度泛函理论(DFT)来研究ATiO3的特性(A=Mn,Fe,Ni)利用GGA和DFT+U形式。我们的结果表明,所研究的化合物在G型反铁磁构型中表现出基态磁性排列。由于过渡金属的电子屏蔽效果较差,沿行取代A位原子会导致体积减小。所有研究的系统在动态条件下都是稳定的,没有想象的声子。根据地层能量计算,NiTiO3被认为是最可成形和最稳定的化合物。DFT+U对FeTiO3最有效,导致与GGA级带隙相比显著更宽的带隙。光学性质,如静态介电常数,折射率,与DFT+U结果相比,GGA高估了反射率。分析了FeTiO3,MnTiO3和NiTiO3的吸收边缘,与GGA相比,DFT+U显示延迟发作。根据DFT+U,发现FeTiO3是可见光谱内最有效的吸收剂,而NiTiO3被GGA预测为最佳吸收剂。根据Born标准对每种化合物的机械稳定性进行了测试和验证,FeTiO3在DFT+U下表现出最高的弹性模量,根据GGA,NiTiO3具有最高的剪切和杨氏模量。在研究的化合物中,FeTiO3是最佳性能和最有效的压电化合物,在DFT+U下e_16=5.418Cm^(-2)。总的来说,所研究的化合物在光伏器件领域具有广泛的应用前景,和压电材料,由于它们非凡的光学,和压电性能。
This work employs Density Functional Theory (DFT) to investigate the characteristics of ATiO3 (A= Mn, Fe, Ni) by utilizing GGA and DFT+U formalisms. Our results reveal that the investigated compounds exhibit a ground-state magnetic arrangement in the G-type antiferromagnetic configuration. Substitution of the A-site atoms along the row leads to a decrease in volume due to poor electronic shielding effects with transition metals. All systems investigated are stable under dynamical conditions, with no imaginary phonon. From the formation energy calculations, NiTiO3 was identified as the most formable and stable compound. DFT+U was most effective for FeTiO3, resulting in significantly wider bandgaps compared to the GGA-level bandgaps. Optical properties such as static dielectric constants, refractive index, and reflectivity were overestimated by the GGA when compared to DFT+U results. The absorption edges of FeTiO3, MnTiO3, and NiTiO3 were analyzed, with DFT+U showing delayed onset compared to GGA. FeTiO3 was found to be the most effective absorber within the visible spectrum according to DFT+U, while NiTiO3 was predicted to be the best absorber by GGA. Each compound\'s mechanical stability was tested and verified based on the Born criteria, with FeTiO3 exhibiting the highest elastic moduli under DFT+U, while NiTiO3 had the highest shear and Young\'s modulus according to GGA. Among the studied compounds, FeTiO3 is the best-performing and most efficient piezoelectric compound with e_16 = 5.418 C m^(-2) under DFT+U. Overall, the studied compounds demonstrate promising capabilities for a wide range of applications in the field of photovoltaic devices, and piezoelectric materials, due to their remarkable optical, and piezoelectric properties.