scholarly journals Electronic Structure of Ternary Alloys of Group III and Rare Earth Nitrides

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4115
Author(s):  
Maciej J. Winiarski
Keyword(s):  
Electronic Structure ◽  
Rare Earth ◽  
Band Gap ◽  
Electronic Structures ◽  
Structural Parameters ◽  
Ternary Alloys ◽  
Experimental Investigations ◽  
Ion Content ◽  
Group Iii ◽  
Rare Earth Nitrides

Electronic structures of ternary alloys of group III (Al, Ga, In) and rare earth (Sc, Y, Lu) nitrides were investigated from first principles. The general gradient approximation (GGA) was employed in predictions of structural parameters, whereas electronic properties of the alloys were studied with the modified Becke–Johnson GGA approach. The evolution of structural parameters in the materials reveals a strong tendency to flattening of the wurtzite type atomic layers. The introduction of rare earth (RE) ions into Al- and In-based nitrides leads to narrowing and widening of a band gap, respectively. Al-based materials doped with Y and Lu may also exhibit a strong band gap bowing. The increase of a band gap was obtained for Ga1−xScxN alloys. Relatively small modifications of electronic structure related to a RE ion content are expected in Ga1−xYxN and Ga1−xLuxN systems. The findings presented in this work may encourage further experimental investigations of electronic structures of mixed group III and RE nitride materials because, except for Sc-doped GaN and AlN systems, these novel semiconductors were not obtained up to now.

First-principles studies on electronic structures and optical properties of two-dimensional Sn1−xTi(Zr)xS2 alloys

2018 ◽  
Vol 32 (07) ◽  
pp. 1850092 ◽  
Author(s):  
Dandan Li ◽  
Juan Du ◽  
Qian Zhang ◽  
Congxin Xia ◽  
Shuyi Wei
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Threshold Energy ◽  
Ternary Alloys ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Experimental Conditions ◽  
Part Formula

Through first-principles calculations we study the electronic structures and optical properties of two-dimensional (2D) Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys. The results indicate that the band gap value of Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys is decreased continuously when Ti(Zr) concentration is increased, which is very beneficial to optoelectronic devices applications. Moreover, the static dielectric constant is increased when the Ti(Zr) concentration is increased in the 2D Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys. In addition, we also calculate the imaginary part [Formula: see text] dispersion of Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys along the plane with different Ti(Zr) concentrations. The threshold energy values decrease with increasing Ti(Zr) concentrations in the Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 ternary alloys. Moreover, the calculations of formation energy also indicate that these 2D alloys can be fabricated under some experimental conditions. These results suggest that Ti(Zr) substituting Sn atom is an efficient way to tune the band gap and optical properties of 2D SnS2 nanosheets.

Structural parameters, band-gap bowings and phase diagrams of zinc-blende Sc1−xInxP ternary alloys: A FP-LAPW study

2013 ◽  
Vol 574 ◽  
pp. 124-130 ◽  
Author(s):  
William López-Pérez ◽  
Nicolás Simon-Olivera ◽  
Javier Molina-Coronell ◽  
Alvaro González-García ◽  
Rafael González-Hernández
Keyword(s):  
Band Gap ◽  
Phase Diagrams ◽  
Structural Parameters ◽  
Ternary Alloys ◽  
Zinc Blende

scholarly journals First principles study of IIIA atoms adsorbed on ZnO (0001) surface and the applications in optoelectronic devices

2021 ◽  
Vol 2083 (2) ◽  
pp. 022002
Author(s):  
Haifeng Zhang ◽  
Caiping Cheng ◽  
Bin Wang
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Formation Energy ◽  
Optoelectronic Devices ◽  
Adsorption Behavior ◽  
Binding Ability ◽  
Impurity States ◽  
Adsorption Sites

Abstract First principles method is used to study the adsorption behavior, formation energy and electronic structure of IIIA (B, Al, Ga, In) atoms adsorbed on Top, T4 and H3 sites of ZnO (0001) surface. The date shows that the formation energy of B, Al, Ga and In atoms adsorbed on Top site is highest, then followed by T4 site, and H3 is a more stable adsorption site. With the periodic increase of B, Al, Ga and In atoms, the formation energy of corresponding models decreases gradually, and the binding ability with O atoms also decreases gradually. The electronic structure of ZnO (0001) surface is sensitive to the adsorption sites. When these atoms are adsorbed on Top sites, the electronic structures of B-Top, Al-Top, Ga-Top and In-Top models have a little change compared with ZnO (0001) surface. However, when these atoms are adsorbed on T4 and H3 sites, the impurity states appear on the VBM, which narrowing the band gap of the corresponding models.

scholarly journals Electronic Structure of the Rare-Earth Nitrides

2021 ◽  
Author(s):  
◽  
A. R. H. Preston
Keyword(s):  
Electronic Structure ◽  
Rare Earth ◽  
Band Structure ◽  
Electronic Band Structure ◽  
Electronic Band ◽  
X Ray ◽  
Rare Earth Nitrides ◽  
Wide Range ◽  
X Ray Absorption ◽  
The Rare Earth

<p>The rare-earth nitrides (ReNs) are a class of novel materials with potential for use in spintronics applications. Theoretical studies indicate that among the ReNs there could be half-metals, semimetals and semiconductors, all exhibiting strong magnetic ordering. This is because of the complex interaction between the partially filled rare-earth 4f orbital and the nitrogen 2p valence and rare-earth 5d conduction bands. This thesis uses experimental and theoretical techniques to probe the ReN electronic structure. Thin films of SmN, EuN, GdN, DyN, LuN and HfN have been produced for study. Basic characterization shows that the films are of a high quality. The result of electrical transport, magnetometry, and optical and x-ray spectroscopy are interpreted to provide information on the electronic structure. SmN, GdN, DyN are found to be semiconductors in their ferromagnetic ground state while HfN is a metal. Results are compared with density functional theory (DFT) based calculations. The free parameters resulting from use of the local spin density approximation with Hubbard-U corrections as the exchange-correlation functional are adjusted to reach good agreement with x-ray absorption and emission spectroscopy at the nitrogen K-edge. Resonant x-ray emission is used to experimentally measure valence band dispersion of GdN. No evidence of the rare-earth 4f levels is found in any of the K-edge spectroscopy, which is consistent with the result of M-edge x-ray absorption which show that the 4f wave function of the rare-earths in the ReNs are very similar to those of rare-earth metal. An auxillary resonant x-ray emission study of ZnO is used to map the dispersion of the electronic band structure across a wide range of the Brillouin zone. The data, and calculations based on GW corrections to DFT, together provide a detailed picture of the bulk electronic band structure.</p>

scholarly journals Crystal structure of rare earth and group III nitride alloys by ab initio calculations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Maciej J. Winiarski ◽  
Dorota A. Kowalska
Keyword(s):  
Rare Earth ◽  
Density Functional ◽  
Metastable Phase ◽  
Rare Earth Ions ◽  
Ternary Alloys ◽  
Wurtzite Phase ◽  
Functional Theory ◽  
Group Iii ◽  
The Density Functional Theory ◽  
Group Iii Nitride

Abstract The ground state phases of ternary alloys of rare earth and group III nitride semiconductors have been investigated within the density functional theory. The most energetically favorable crystal phases among possible cubic and hexagonal structures, i.e., the rock salt, zinc blende, wurtzite, and hexagonal BN, were determined. The type of a unit cell and the lattice parameters of the materials are presented as a function of their composition. Furthermore, effects of strain on ground states of group III and rare earth nitride materials are discussed. The findings presented in this work discloses the wurtzite type materials as being stable with relatively low contents of rare earth elements. It is expected that the wurtzite phase will be very persistent only in the La-based systems. Nevertheless, the two-dimensional hexagonal atomic layers are revealed as being a metastable phase for all alloys studied. This finding supports the conclusion of previous experimental reports for Sc-doped GaN systems that the presence of rare earth ions in group III nitride materials leads to flattening of the wurtzite type layers.

Electronic structure modification in two-dimensional pentagonal PdS2 by external strain

2021 ◽  
Author(s):  
Mridu Sharma ◽  
Ranber Singh
Keyword(s):  
Electronic Structure ◽  
Band Gap ◽  
Valence Band ◽  
Electronic Structures ◽  
Two Dimensional ◽  
Structure Modification ◽  
Indirect Band Gap ◽  
D Orbitals ◽  
External Strain

We investigated the electronic structure modifications in two-dimensional (2D) pentagonal PdS<sub>2</sub> materials by external strains. In the absence of external strain the 2D pentagonal PdS<sub>2</sub> materials are indirect band gap semiconductors. The band gap decreases with an increase in the number of stacking PdS<sub>2</sub> monolayers. The external uniaxial and biaxial strains significantly modify the contributions of p-orbitals of S atoms and d-orbitals of Pd atoms to the conduction and valence band edges. It consequently modify the electronic structures of 2D pentagonal PdS<sub>2</sub> materials. This strain tunability of electronic structures of 2D pentagonal PdS<sub>2</sub> materials may be useful for their electro-mechanical applications.

Theoretical investigation of dielectric properties of rare earth stillwellite compounds

2015 ◽  
Vol 29 (21) ◽  
pp. 1550154
Author(s):  
R. Shaltaf ◽  
J. Khalifeh
Keyword(s):  
Electronic Structure ◽  
Rare Earth ◽  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
High Frequency ◽  
Density Functional ◽  
Structural Parameters ◽  
The Other ◽  
Static Dielectric Permittivity ◽  
Dielectric Tensors

Ab initio density functional calculations are performed to investigate the dielectric properties of LnBSiO 5 (Ln = Ce, Pr, Nd) with the stillwellite structure. The calculated structural parameters are found to agree well with existing experimental results. The three compounds possess insulating electronic structure with nearly isotropic high frequency dielectric permittivity tensors. On the other hand, the static dielectric permittivity tensors are found to be less isotropic. The anisotropy of static dielectric tensors are found to increase as the atomic number of the lanthanide increases.

scholarly journals First Principles Study on Electronic Structure and Optical Properties of PMMA Doped InSb–Mn Alloy Polymer Matrix Composite

2022 ◽  
Vol 2022 ◽  
pp. 1-6
Author(s):  
Dhanabalakrishnan Kovilpalayam Palaniswamy ◽  
Pandiyan Arumugan ◽  
Ravindiran Munusami ◽  
A Chinnasamy ◽  
S. Madhu ◽  
...  
Keyword(s):  
Thin Film ◽  
Optical Properties ◽  
Electronic Structure ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Optical Conductivity ◽  
First Principles ◽  
Dft Method ◽  
Optical Absorption Coefficient ◽  
Group Iii

InSb the group III-V semiconductor with narrow band gap is combined with Mn in various concentrations and that InSb–Mn alloy is doped with poly methyl methacrylate (PMMA). The optical properties and electronic structure of ternary InSb–Mn alloy with PMMA are investigated by first principles calculations using the DFT method. Varying Mn concentrations play an important role in the improvement of the absorption coefficient and optical conductivity. It is observed that the band gap of InSb–Mn: PMMA decreases monotonously with the increase in Mn concentration. Optical properties of InSb–Mn: PMMA, such as the optical absorption coefficient and optical conductivity, are greater than those of pure InSb. InSb–Mn: PMMA alloy is doped with PMMA polymer in order to make a thin film as PMMA is a transparent thermoplastic polymer. These results suggest a promising application of InSb–Mn: PMMA thin film in optoelectronics when the InSb doping is 24% with improved conductivity when compared with other doping ratios. This states the optimum doping ratio and the major finding in the carried out research based on modelling and simulation.

scholarly journals Electric Field Controlled Indirect-Direct-Indirect Band Gap Transition in Monolayer InSe

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Xian-Bo Xiao ◽  
Qian Ye ◽  
Zheng-Fang Liu ◽  
Qing-Ping Wu ◽  
Yuan Li ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Band Gap ◽  
Energy Band ◽  
Electronic Structures ◽  
Optoelectronic Devices ◽  
Group Iii ◽  
Underlying Mechanisms ◽  
Indirect Band Gap

Abstract Electronic structures of monolayer InSe with a perpendicular electric field are investigated. Indirect-direct-indirect band gap transition is found in monolayer InSe as the electric field strength is increased continuously. Meanwhile, the global band gap is suppressed gradually to zero, indicating that semiconductor-metal transformation happens. The underlying mechanisms are revealed by analyzing both the orbital contributions to energy band and evolution of band edges. These findings may not only facilitate our further understanding of electronic characteristics of layered group III-VI semiconductors, but also provide useful guidance for designing optoelectronic devices.

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