Publications by authors named "Thamer Alharbi"

4 Publications

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Revealing the optoelectronic properties of Re-based double perovskites using the Tran-Blaha modified Becke-Johnson with density functional theory.

J Mol Model 2020 May 28;26(6):158. Epub 2020 May 28.

School of Physical Science and Technology, Southwest University, Chongqing, 400715, China.

Density functional theoretical (DFT) calculations were carried out to explore the electronic and optical properties of double ordered BaNaReO, BaLiReO, and SrLiReO perovskites by employing the state-of-the-art exchange-correlation potential, i.e., Tran-Blaha modified Becke-Johnson for the electronic system. The calculated electronic band structures show an indirect band gap along with a semiconductor nature. Total and partial densities of state peaks were analyzed in light of effective contributions of various electronic states. The significant optical parameters, including the components of dielectric constant, the energy loss function, the absorption coefficient, the reflectivity spectra, the refractive index, and the extinction coefficient, were computed and discussed in details for radiation up to 14 eV. Finally, we studied the inter-band contributions from the optical characteristics. Our present study might be considered as first theoretical quantitative calculations of the optical and electronic behavior in the cubic phase of double perovskite materials based on rhenium.
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http://dx.doi.org/10.1007/s00894-020-04421-5DOI Listing
May 2020

Dual-Color Lasing Lines from EMPs in Diluted Magnetic Semiconductor CdS:NiI Structure.

Research (Wash D C) 2019 5;2019:6956937. Epub 2019 Nov 5.

Department of Physics, College of Science, Majmaah University, Al-Majmaah 11952, Saudi Arabia.

Have one ever seen a semiconductor that can issue two-color lasing lines? The diluted magnetic semiconductor (DMS) can do this. Here, we have observed dual lasing lines of 530 nm and 789 nm from a DMS structure of CdS:NiI, in which the excitonic magnetic polaron (EMP) and localized excitonic magnetic polaron (LEMP) are excitations out of ferromagnetic (NiS) nanocluster and NiI nanoclusters within CdS lattice; both of them could lead to the collective EMP state at high excitation and therein produce coherent emission lines simultaneously. This occurrence is due to the superposition of EMP near CdS bandedge and the combination of the charge-transfer band of (NiI) cluster with the LEMP within CdS lattice by overcoming the strong electron correlation of NiI cluster in a DMS structure, evidenced also by ab initio calculation. This finding opens a way to understand the collective behaviour of spin-coupled excitons in DMS and to find novel applications in the spin-related quantum technology.
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http://dx.doi.org/10.34133/2019/6956937DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6944495PMC
November 2019

Electronic structure and optical properties of TaNO: An ab initio study.

J Mol Graph Model 2019 11 10;92:296-302. Epub 2019 Aug 10.

School of Physical Science and Technology, Southwest University, Chongqing, 400715, China. Electronic address:

We performed ab initio calculations to study the structural and optoelectronic properties of simple and slab phase TaNO using density functional theory (DFT), in which the full potential augmented plane wave (FP-LAPW) method was implemented using the computational code Wien 2k. The modified Becke-Johnson potential (mBJ-GGA) was used for these calculations. The calculated band structure and electronic properties revealed an indirect bandgap for simple TaNO (3.2 eV) and a direct bandgap for slab TaNO (1.5 eV). The interband electronic transitions were investigated from the band structure, and transition peaks were observed from the imaginary part of the dielectric function. These transitions are due to Ta-p, N-p and O-p orbitals for simple TaNO and Ta-p, N-s as well as O-p orbitals for slab TaNO. The plasmon energy was related to the main peak of the energy loss function, which was approximately 10 eV. The static value of the dielectric constant and the refraction were close to the experimental values. In general, slab TaNO shows different properties and is more suitable for optoelectronic applications due to direct bandgap.
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http://dx.doi.org/10.1016/j.jmgm.2019.08.006DOI Listing
November 2019

Transfer factors for natural radioactivity into date palm pits.

J Environ Radioact 2017 Feb 25;167:75-79. Epub 2016 Nov 25.

Al-majmaah University, Al-Zulfi, Saudi Arabia. Electronic address:

Palm pits are used in various human and animal feed products. In this study, the natural radioactivity levels from soil and date palm pits of 9 samples collected from major date palm farms in three different regions (Buraidah, Al-Zulfi and Al-Majmaah) of Saudi Arabia were determined by using the high purity germanium (HPGe) gamma-ray spectrometer. The mean activity concentrations of Ra, Th, Cs and K in soil samples were 12.8 ± 2.2, 10.2 ± 2.1, 0.28 ± 0.10 and 329 ± 87 Bg kg, respectively. Similarly the mean activity concentrations of Ra, Th, and K in date palm pits were 5.6 ± 1.2, 2.8 ± 0.4 and 181 ± 17 Bq kg, respectively, whereas Cs could not be detected. The geometric mean of TF values (geometric standard deviation in parentheses) of Ra, Th, and K were 0.33 (2.1), 0.22 (1.8) and 0.51 (2.0), respectively.
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http://dx.doi.org/10.1016/j.jenvrad.2016.11.014DOI Listing
February 2017
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