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Graphical abstract The maximum absorption exists in the visible light region for all the phases studied; making In-doped AlFeO 3 suitable for energy harvesting applications. Highlights • Electron effective mass is smaller than that of holes for Al 1−x In x FeO 3. • Effective electron mass tensor is fairly isotropic; hole mass is not so. • High dielectric-constants of Al 1−x In x FeO 3 indicate promise for charge separation. • Reflectivity peaks for all the phases is found near IR and UV region. • Absorption-spectra indicate relevance for visible light harvesting. Abstract Electronic and optical properties of AlFeO 3 and Al 1−x In x FeO 3 (x = 0.25, 0.5, 0.75) are studied using ab-initio calculations. Electronic structure in the vicinity of the conduction band minimum (CBM) and valence band maximum (VBM), the effective masses of holes and electrons at the gamma point are calculated. The calculated effective masses of electrons is smaller than that of holes (m c1 ⊥, m c1 ‖ (m e *) < m v1 ⊥, m v1 ‖, m v2 ⊥, m v2 ‖ (m h *)), for all values of x; this is expected to contribute to the desirable photocatalytic performance. Effective mass tensor for electrons is found to be isotropic (unlike holes). The optical constants such as static dielectric constant, refractive index, extinction coefficient and absorption coefficient are comparable with that Si. The maximum absorption exists in the visible light region for all the phases studied; making In-doped AlFeO 3 suitable for energy harvesting applications. We noted from our previous work (Sudha Priyanga and Thomas, 2018) that the computed band gap values could be underestimated by as large as ∼0.5 eV. Even so, the reported phases would be relevant for light harvesting. [ABSTRACT FROM AUTHOR]

[Display omitted] Monolayer Indium Selenide (ML-InSe) is studied for 4x4 supercell structure through ab initio calculations. The electronic and optical properties of ML-InSe for both pristine and substitutional doped ML-InSe with Palladium (Pd), Platinum (Pt), Silver (Ag), and Gold (Au) atoms have been calculated. With substitutional doping, ML-InSe has been observed to have a spin-dependent electronic structure. The flat energy bands near the Fermi level are observed in ML-InSe with doping elements placed in In site. The flat bands of d orbitals of some noble metal atoms are formed by the projected density of states (PDOS). The PDOS calculations show that the s-orbital of In and p-orbital of Se form the conduction band edge. The energetically favorable position of doping atoms is found to be the Pt In substitution atom according to formation energy calculations. For each studied structure, the bond length of the first neighbor of doping atoms in doped ML-InSe, static dielectric constant (ε 0), refractive index, and energy band gap have been calculated. In the structure ML-InSe with Au Se , ε 0 reaches ∼ 8.15. Another important result is that substitutional doping induces some peaks in the lower energy region of the imaginary part of the dielectric function. These peaks mainly refer to the absorption in related regions and may be important for the optoelectronic properties of ML-InSe. [ABSTRACT FROM AUTHOR]

Abstract: We have implemented the calculation of optical matrix elements with and without the inclusion of a real-space cutoff in the open-source software package ABINIT. We have also included the possibility to add the contribution arising from the non-local term of the pseudopotential operator. The implementation has been tested successfully for atoms, bulk silicon, and an oxidized silicon surface. [ABSTRACT FROM AUTHOR]

[Display omitted] Mayenite (12CaO · 7Al 2 O 3 or generally named C12A7) and its electride form (C12A7 : 4 e −) have drawn intensive attention because of a variety of promising applications including display devices, catalysis, and transistors. C12A7 is a transparent insulator and it can be controllably engineered to a conductor or superconductor upon introducing oxygen vacancies and substitutional anionic impurities. However, the influence of external pressure on electronic and optical properties of C12A7 remains intriguingly less explored. On the basis of the density functional theory (DFT) and ab initio molecular dynamics, this work presents the variations of electronic and optical properties of C12A7 via the immense external pressure. The findings reveal that the applied pressure induces the structural deformation until it is energetically amorphised at pressure greater than 17.94 GPa. Such deformation consequently creates the gradual reduction in the electronic band gap because of the intensified overlap of electronic bands among the framework Ca-3 d , O-2 p , and the in-cage extra-framework O-2 p states. Furthermore, the drop in the band gap yields the remarkable enhancement in the optical absorbance in the visible and UV regions. Our findings unveil the underlying influences of the external pressure on the C12A7 properties which are of fundamental interests and functional design for applications. [ABSTRACT FROM AUTHOR]