Thermoelectric Properties of Sm Doped CaMnO3 Using Density Functional Theory Method

2020 ◽  
Vol 1010 ◽  
pp. 334-338
Author(s):  
Abdullah Chik ◽  
Ruhiyuddin Mohd Zaki ◽  
Akeem Adekunle Adewale ◽  
Faizul Che Pa ◽  
Yeoh Cheow Keat
Keyword(s):  
Thermal Conductivity ◽  
Density Functional Theory ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Temperature Dependence ◽  
Band Gap ◽  
Thermoelectric Properties ◽  
Density Functional ◽  
Electronic Band ◽  
Functional Theory

The electronic structure and thermoelectric properties of CaMnO3 doped with 8% and 17% f block element Sm using first principles calculations and semi-classic Boltzmann theory were presented in this paper. The G-type AFM phase is most stable among five phases for CaMnO3, however, with 8% and 17% Sm doping, these compounds became nonmagnetic phases. CaMnO3 calculated electronic band structure shows an indirect band gap of 0.523 eV, which is underestimated by the density functional theory (DFT) calculations but the band gap explains the semiconducting behavior. However, with 8% and 17% Sm doping, the electronic bandstructure of these compounds exhibit metallic behavior, with Sm and Mn 3d electrons contributing to conduction band, increasing the magnitude of conductivity for doped compounds. All temperature dependence Seebeck coefficient plots show n-typed conduction for all compound with reduced magnitude of Seebeck coefficient for doped compounds. The temperature dependence thermal conductivity plot shows overall thermal conductivity is reduced in Sm doped compound. CaMnO3 with 17% Sm doping exhibit much higher ZT of 0.32 at 800 K showing enhanced thermoelectric properties at high temperature and suitability or high temperature energy conversion devices.

scholarly journals Giant magnetoresistance and spin Seebeck coefficient in zigzag α-graphyne nanoribbons

Nanoscale ◽  
2014 ◽  
Vol 6 (19) ◽  
pp. 11121-11129 ◽  
Author(s):  
Ming-Xing Zhai ◽  
Xue-Feng Wang ◽  
P. Vasilopoulos ◽  
Yu-Shen Liu ◽  
Yao-Jun Dong ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Green's Function ◽  
Density Functional ◽  
Function Method ◽  
Giant Magnetoresistance ◽  
Functional Theory ◽  
Non Equilibrium Green’S Function ◽  
Non Equilibrium

We investigate the spin-dependent electric and thermoelectric properties of ferromagnetic zigzag α-graphyne nanoribbons (ZαGNRs) using density-functional theory combined with non-equilibrium Green's function method.

scholarly journals Electronic, magnetic, optical and thermoelectric properties of Ca2Cr1−xNixOsO6 double perovskites

RSC Advances ◽  
2020 ◽  
Vol 10 (27) ◽  
pp. 16179-16186 ◽  
Author(s):  
Shalika R. Bhandari ◽  
D. K. Yadav ◽  
B. P. Belbase ◽  
M. Zeeshan ◽  
B. Sadhukhan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Thermoelectric Properties ◽  
Density Functional ◽  
Double Perovskite ◽  
Density Functional Theory Calculations ◽  
Double Perovskites ◽  
Functional Theory ◽  
Perovskite Material

With the help of density functional theory calculations, we explored the recently synthesized double perovskite material Ca2CrOsO6 and found it to be a ferrimagnetic insulator with a band gap of ∼0.6 eV.

Effect of Al Excess on the Band Structure of ZnO Using Density Functional Theory

2016 ◽  
Vol 857 ◽  
pp. 106-110
Author(s):  
J.H. Lim ◽  
Cheow Keat Yeoh ◽  
Abdullah Chik ◽  
Pei Leng Teh
Keyword(s):  
Electrical Conductivity ◽  
Density Functional Theory ◽  
Band Structure ◽  
Band Gap ◽  
Density Functional ◽  
Band Structure Calculation ◽  
Al Doping ◽  
Electronic Band ◽  
Functional Theory ◽  
Doped Zno

The effect of Al doping to the band structure of ZnO was studied in this paper. The electronic band structure of Al doped ZnO was determined by using first-principles based on density functional theory. ABINIT was used to perform the band structure calculation. The calculated band structure of ZnO and Al doped ZnO shows that ZnO is a direct band gap semiconductor. The band structure become narrow with Al doping compared pure ZnO. With Al doping, the band gap of ZnO (0.749 eV) become smaller as the concentration Al doping increased to 4wt% (0.551 eV). The electrical conductivity of Al doped ZnO was studied as a references value for the band gap. The electrical conductivity of ZnO (8.21 S/cm) was enhanced with Al doping increased to 4wt% (71.87 S/cm).

scholarly journals Screening of II-IV-V2 Materials for Photovoltaic Applications Based on Density Functional Theory Calculations

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 883
Author(s):  
Byeong-Hyeon Jeong ◽  
Minwoo Jeong ◽  
Youbin Song ◽  
Kanghyeon Park ◽  
Ji-Sang Park
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Energy Difference ◽  
Stacking Sequence ◽  
Electronic Band ◽  
Functional Theory ◽  
Photovoltaic Applications ◽  
Calculation Results

The relative stability of polymorphs and their electronic structure was investigated for II-IV-V2 materials by using first-principles density functional theory calculations. Our calculation results show that, for Zn-, Cd-, and Be-containing compounds, nitrides favor the 2H polymorph with AB stacking sequence; however, phosphides, arsenides, and antimonides are more stable in the 3C polymorph with the ABC stacking sequence. The electronic band gap of materials was calculated by using hybrid density functional theory methods, and then materials with an ideal band gap for photovoltaic applications were chosen. The experimental synthesis of the screened materials is reported, except for CdSiSb2, which was found to be unstable in our calculation. The absorption coefficient of the screened materials, especially ZnGeAs2, was high enough to make thin-film solar cells. The higher stacking fault energy in ZnGeAs2 than the others is consistent with the larger formation energy difference between the 2H and 3C polymorphs.

scholarly journals Investigation on the electronic structure, optical, elastic, mechanical, thermodynamic and thermoelectric properties of wide band gap semiconductor double perovskite Ba2InTaO6

RSC Advances ◽  
2019 ◽  
Vol 9 (17) ◽  
pp. 9522-9532 ◽  
Author(s):  
Sajad Ahmad Dar ◽  
Ramesh Sharma ◽  
Vipul Srivastava ◽  
Umesh Kumar Sakalle
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Band Gap ◽  
Thermoelectric Properties ◽  
Density Functional ◽  
Double Perovskite ◽  
Wide Band ◽  
Wide Band Gap ◽  
Functional Theory

In the present paper, double perovskite Ba2InTaO6 was investigated in terms of its structural, electronic, optical, elastic, mechanical, thermodynamic and thermoelectric properties using density-functional theory (DFT).

scholarly journals Synthesis and density-functional-theory calculations of electronic band structure of hollow sphere WS2

2018 ◽  
Vol 36 (3) ◽  
pp. 409-418 ◽  
Author(s):  
Maxwell Selase Akple ◽  
Holali Kwami Apevienyeku
Keyword(s):  
Electron Microscopy ◽  
Density Functional Theory ◽  
Band Gap ◽  
Density Functional ◽  
Large Scale ◽  
Scale Production ◽  
High Quality ◽  
Electronic Band ◽  
Functional Theory ◽  
X Ray

AbstractA novel and low-cost synthesis of tungsten disulfide (WS2) transition metal dichalcogenide was carried out via gas-solid reaction in a horizontal quartz reactor. In this process, the prepared hollow WO3 precursor was sulfided with CS2 at 550 °C at different durations under N2 gas atmosphere. The as-prepared WS2 samples were formed by substitution of O by S during the sulfidation process. The characterization of these samples was performed employing X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET) specific surface area, X-ray photoelectron spectroscopy (XPS) and UV-Vis absorption spectroscopy. The characterization results showed that the as-prepared WS2 samples were of high quality and purity. No significant differences were observed in various WS2 samples synthesized during different sulfidation periods. The calculated results obtained from the density functional theory (DFT) indicate that WS2 has an indirect band gap of ca. 1.56 eV, which is in agreement with experimental band gap of ca. 1.50 eV. Combining the experimental and DFT results suggests that the novel method used in the synthesis of WS2 has a potential application for large scale production. The obtained WS2 are of high quality and can be implemented in photocatalysis, catalysis, photovoltaics, optoelectronic devices and photosensor devices.

A New Approach for Calculating the Band Gap of Semiconductors within the Density Functional Method

2015 ◽  
Vol 242 ◽  
pp. 434-439 ◽  
Author(s):  
Vasilii E. Gusakov
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Density Functional ◽  
Density Functional Method ◽  
Functional Method ◽  
Localized States ◽  
Experimental Accuracy ◽  
Functional Theory ◽  
New Approach ◽  
The Density Functional Theory

Within the framework of the density functional theory, the method was developed to calculate the band gap of semiconductors. We have evaluated the band gap for a number of monoatomic and diatomic semiconductors (Sn, Ge, Si, SiC, GaN, C, BN, AlN). The method gives the band gap of almost experimental accuracy. An important point is the fact that the developed method can be used to calculate both localized states (energy deep levels of defects in crystal), and electronic properties of nanostructures.

Understanding the advantage of hexagonal WO3 as an efficient photoanode for solar water splitting: a first-principles perspective

2016 ◽  
Vol 4 (29) ◽  
pp. 11498-11506 ◽  
Author(s):  
Taehun Lee ◽  
Yonghyuk Lee ◽  
Woosun Jang ◽  
Aloysius Soon
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Water Splitting ◽  
Anode Material ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Good Alternative ◽  
Functional Theory ◽  
Solar Water Splitting

Using first-principles density-functional theory calculations, we investigate the advantage of using h-WO3 (and its surfaces) over the larger band gap γ-WO3 phase for the anode in water splitting. We demonstrate that h-WO3 is a good alternative anode material for optimal water splitting efficiencies.

Band Structure and Thermoelectric Properties of Ni(x)Zn(1-x)Fe2O4

2021 ◽  
Vol 317 ◽  
pp. 28-34
Author(s):  
Joon Hoong Lim
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Band Structure ◽  
Seebeck Coefficient ◽  
Band Gap ◽  
Thermoelectric Properties ◽  
Xrd Analysis ◽  
Valence Band Maximum ◽  
Solid State Method ◽  
Ni Content

Thermoelectric materials has made a great potential in sustainable energy industries, which enable the energy conversion from heat to electricity. The band structure and thermoelectric properties of Ni(x)Zn(1-x)Fe2O4 have been investigated. The bulk pellets were prepared from analytical grade ZnO, NiO and Fe2O3 powder using solid-state method. It was possible to obtain high thermoelectric properties of Ni(x)Zn(1-x)Fe2O4 by controlling the ratios of dopants and the sintering temperature. XRD analysis showed that the fabricated samples have a single phase formation of cubic spinel structure. The thermoelectric properties of Ni(x)Zn(1-x)Fe2O4 pellets improved with increasing Ni. The electrical conductivity of Ni(x)Zn(1-x)Fe2O4 pellets decreased with increasing Ni content. The electrical conductivity of Ni(x)Zn(1-x)Fe2O4 (x = 0.0) is (0.515 x10-3 Scm-1). The band structure shows that ZnxCu1-xFe2O4 is an indirect band gap material with the valence band maximum (VBM) at M and conduction band minimum (CBM) at A. The band gap of Ni(x)Zn(1-x)Fe2O4 increased with increasing Ni content. The increasing band gap correlated with the lower electrical conductivity. The thermal conductivity of Ni(x)Zn(1-x)Fe2O4 pellets decreased with increasing Ni content. The presence of Ni served to decrease thermal conductivity by 8 Wm-1K-1 over pure samples. The magnitude of the Seebeck coefficient for Ni(x)Zn(1-x)Fe2O4 pellets increased with increasing amounts of Ni. The figure of merit for Ni(x)Zn(1-x)Fe2O4 pellets and thin films was improved by increasing Ni due to its high Seebeck coefficient and low thermal conductivity.

Sign in / Sign up

Export Citation Format

Share Document