scholarly journals Scrutinizing the stability and exploring the dependence of thermoelectric properties on band structure of 3d-3d metal-based double perovskites Ba2FeNiO6 and Ba2CoNiO6

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shabir Ahmad Mir ◽  
Dinesh C. Gupta
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Band Structure ◽  
Room Temperature ◽  
Electronic Band Structure ◽  
Double Perovskites ◽  
Electronic Band ◽  
Half Metal ◽  
The Stability ◽  
Wasted Energy

AbstractThrough the conventional DFT computation, we have designed new oxide double perovskites Ba2FeNiO6 and Ba2CoNiO6. The structural and thermodynamic stabilities are predicted by optimizing the crystal structure and evaluation of enthalpy of formation, respectively. Then by using the optimized lattice constant, we have explored the different physical properties. The GGA + mBJ electronic band-structure illustrates Ba2FeNiO6 is a half-metal with 100% spin polarization at the Fermi level. While Ba2CoNiO6 shows a ferromagnetic semiconducting nature. The change in the electronic structure when Fe is replaced by Co is explained with the help of the orbital diagram and exchange interaction. The eg-eg hybridization that happens via O-p states is strong because Fe–O–Ni and Co–O–Ni bond angles are strictly 180°. The narrow bandgaps in the semiconducting channels prompted us to analyze the applicability of these materials towards thermoelectric technology. Besides this, we have investigated the dependency of transport properties on electronic band structure. The semiconducting nature in Ba2CoNiO6 results in a significant ZT around 0.8 at room temperature makes it suitable for wasted-energy regeneration

scholarly journals Scrutinizing the Stability and Exploring the Dependence of Thermoelectric Properties on Band Structure of 3d Metal-Based Double Perovskites: An ab-initio Analysis

2021 ◽  
Author(s):  
Shabir Ahmad Mir ◽  
Dinesh C. Gupta
Keyword(s):  
Band Structure ◽  
Transport Properties ◽  
Exchange Interaction ◽  
Electronic Band Structure ◽  
Double Perovskites ◽  
Electronic Band ◽  
Band Profile ◽  
Strong Exchange ◽  
The Stability ◽  
Cohesive Energies

Abstract Through the conventional DFT computation, we have designed new oxide double perovskites Ba2BNiO6 (B = Fe and Co). The structural and thermodynamic stabilities are defined by optimizing the crystal energy and determination of tolerance factor and cohesive energies. Thereafter, at the optimized lattice constant, we have explored the different physical properties. The GGA+mBJ electronic band-structure depicts the semiconducting nature for Ba2CoNiO6 while half-metallic with 100% spin polarization for Ba2FeNiO6. The origin of such a diverse band profile upon changing Fe to Co is explained with the help of the orbital diagram and exchange interaction. The eg-eg interaction is strong in these perovskites compared to eg-t2g and t2g-t2g hybridization. The strong exchange interaction among eg states via O-p states happens because the B-O-Ni angle is strictly 180°. Furthermore, due to the narrow bandgaps, we have explored the transport properties to express the applicability of these materials towards thermoelectric technology. Also, herein we have investigated the dependency of transport properties on band profile. The semiconducting nature in Ba2CoNiO6 results in a high ZT~0.8 at room temperature makes it suitable for energy restoration.

Energy band alignment at the heterointerface between a nanostructured TiO2 layer and Au22(SG)18 clusters: relevance to metal-cluster-sensitized solar cells

Nanoscale ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 175-184
Author(s):  
Liudmila L. Larina ◽  
Oleksii Omelianovych ◽  
Van-Duong Dao ◽  
Kyunglim Pyo ◽  
Dongil Lee ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Solar Cells ◽  
Band Structure ◽  
Electronic Band Structure ◽  
Metal Cluster ◽  
Band Alignment ◽  
Tio2 Layer ◽  
Electronic Band ◽  
Xps Study ◽  
Sensitized Solar Cells

XPS study of the electronic structure of the Au22(SG)18 clusters and their interface with TiO2 reveals that tailoring of the electronic band structure at the interface can be exploited to increase the efficiency of metal-cluster-sensitized solar cells.

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>

Electronic structure inspired a highly robust electrocatalyst for the oxygen-evolution reaction

2020 ◽  
Vol 56 (58) ◽  
pp. 8071-8074
Author(s):  
Peng Zhang ◽  
Ying-Rui Lu ◽  
Chia-Shuo Hsu ◽  
Huai-Guo Xue ◽  
Ting-Shan Chan ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Electronic Band Structure ◽  
Electronic Band

We demonstrated that the electronic-band structure holds the key to electrocatalytic durability towards the oxygen-evolution reaction (OER).

scholarly journals The occupied electronic structure of ultrathin boron doped diamond

2020 ◽  
Vol 2 (3) ◽  
pp. 1358-1364
Author(s):  
A. C. Pakpour-Tabrizi ◽  
A. K. Schenk ◽  
A. J. U. Holt ◽  
S. K. Mahatha ◽  
F. Arnold ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Band Structure ◽  
Diamond Film ◽  
Photoelectron Spectroscopy ◽  
Electronic Band Structure ◽  
Boron Doped Diamond ◽  
Electronic Band ◽  
Boron Doped

Using angle-resolved photoelectron spectroscopy, we compare the electronic band structure of an ultrathin (1.8 nm) δ-layer of boron-doped diamond with a bulk-like boron doped diamond film (3 μm).

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