Synthesis and Characterization of Novel Nanoparticles of Lithium Aluminum Iodate LiAl(IO3)4, and DFT Calculations of the Crystal Structure and Physical Properties

Here we report on the non-hydrothermal aqueous synthesis and characterization of nanocrystalline lithium aluminum iodate, LiAl(IO3)4. Morphological and compositional analyses were carried out by using scanning electron microscopy (SEM) and energy-dispersive X-ray measurements (EDX). The optical and vibrational properties of LiAl(IO3)4 have been studied by UV-Vis and IR spectroscopy. LiAl(IO3)4 is found to crystallize in the non-centrosymmetric, monoclinic P21 space group, contrary to what was reported previously. Theoretical simulations and Rietveld refinements of crystal structure support this finding, together with the relatively high Second Harmonic Generation (SGH) response that was observed. Electronic band structure calculations show that LiAl(IO3)4 crystal has an indirect band gap Egap=3.68 eV, in agreement with the experimental optical band gap Egap=3.433 eV. The complex relative permittivity and the refraction index of LiAl(IO3)4 have also been calculated as a function of energy, as well as its elastic constants and mechanical parameters. LiAl(IO3)4 is found to be a very compressible and ductile material. Our findings imply that LiAl(IO3)4 is a promising material for optoelectronic and non -linear optical applications.

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Structural, Electronic and Vibrational Properties of YAl3(BO3)4

Materials ◽

10.3390/ma13030545 ◽

2020 ◽

Vol 13 (3) ◽

pp. 545 ◽

Cited By ~ 4

Author(s):

Aleksandr S. Oreshonkov ◽

Evgenii M. Roginskii ◽

Nikolai P. Shestakov ◽

Irina A. Gudim ◽

Vladislav L. Temerov ◽

...

Keyword(s):

Crystal Structure ◽

Band Gap ◽

Density Functional ◽

Dielectric Material ◽

Electronic Band Structure ◽

Vibrational Properties ◽

Electronic Band ◽

Functional Theory ◽

Dynamical Properties ◽

Indirect Band Gap

The crystal structure of YAl3(BO3)4 is obtained by Rietveld refinement analysis in the present study. The dynamical properties are studied both theoretically and experimentally. The experimental Raman and Infrared spectra are interpreted using the results of ab initio calculations within density functional theory. The phonon band gap in the Infrared spectrum is observed in both trigonal and hypothetical monoclinic structures of YAl3(BO3)4. The electronic band structure is studied theoretically, and the value of the band gap is obtained. It was found that the YAl3(BO3)4 is an indirect band gap dielectric material.

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Ab initio calculations of electronic band structure of CdMnS semimagnetic semiconductors

Doklady BGUIR ◽

10.35596/1729-7648-2021-19-8-45-49 ◽

2022 ◽

Vol 19 (8) ◽

pp. 45-49

Author(s):

M. А. Mehrabova ◽

N. T. Panahov ◽

N. H. Hasanov

Keyword(s):

Crystal Structure ◽

Band Structure ◽

Ab Initio Calculations ◽

Ab Initio ◽

Band Gap ◽

Density Functional ◽

Electronic Band Structure ◽

Local Spin Density Approximation ◽

Electronic Band ◽

Semimagnetic Semiconductors

This work is devoted to theoretical investigations of Cd1-xMnxS semimagnetic semiconductors (SMSC). The purpose of this work was to calculate the electronic band structure of ideal and defective Cd1- xMnxS SMSC in both antiferromagnetic (AFM) and ferromagnetic (FM) phases. Ab initio, calculations are performed in the Atomistix Toolkit (ATK) program within the Density Functional Theory (DFT) and Local Spin Density Approximation (LSDA) on Double Zeta Double Polarized (DZDP) basis. We have used Hubbard U potential UMn = 3.59 eV for 3d states for Mn atoms. Supercells of 8 and 64 atoms were constructed. After the construction of Cd1-xMnxS (x = 6.25 %; 25 %) supercells and atom relaxation and optimization of the crystal structure were carried out. Electronic band structure and density of states were calculated, the total energy has been defined in antiferromagnetic (AFM) and ferromagnetic (FM) phases. Our calculations show that the band gap increases with the increase in Mn ion concentration. It has been established that Cd or S vacancy in the crystal structure leads to the change of band gap, Fermi level shifts towards the valence or conduction band.

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