First-Principles Calculation of the Electronic Structure of SrTiO3

The electronic structure, band structure, density of states (DOS) and electronic density difference of paraelectric SrTiO3 in the cubic phase were performed by the first-principles calculation based on the density functional theory (DFT). The energy levels of high symmetry points in the Brillouin zone were listed and Mulliken population analysis was performed for valence bond structures. The top valence band of SrTiO3 is at the R point, and the minimum of the conduction bands is at the Γ point. The calculated value for indirect band gap is 1.84eV in the Brillouin zone. As in other perovskite ABO3 ferroelectrics, the population analysis, DOS and electron density difference show that there is a very strong hybridization between the Ti3d and O2p states in the valence bands, which is responsible for the ferroelectricity tendency.

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Effect of Alloying Elements V, Cr and Ni on the Electronic Structure and Mechanical Properties of FeAl from First-Principles Calculation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.887-888.378 ◽

2014 ◽

Vol 887-888 ◽

pp. 378-383 ◽

Cited By ~ 2

Author(s):

Yu Chen ◽

Zheng Jun Yao ◽

Ping Ze Zhang ◽

Dong Bo Wei ◽

Xi Xi Luo ◽

...

Keyword(s):

Mechanical Properties ◽

Electronic Structure ◽

Elastic Constants ◽

First Principles ◽

Density Functional ◽

Valence Bond ◽

Ternary Alloys ◽

First Principles Calculation ◽

Structure Stability ◽

Alloying Element

The structure stability, mechanical properties and electronic structures of B2 phase FeAl intermetallic compounds and FeAl ternary alloys containing V, Cr or Ni were investigated using first-principles density functional theory calculations. Several models are established. The total energies, cohesive energies, lattice constants, elastic constants, density of states, and the charge densities of Fe8Al8 and Fe8XAl7 ( X=V, Cr, Ni ) are calculated. The stable crystal structures of alloy systems are determined due to the cohesive energy results. The calculated lattice contants of Fe-Al-X ( X= V, Cr, Ni) were found to be related to the atomic radii of the alloy elements. The calculation and analysis of the elastic constants showed that ductility of FeAl alloys was improved by the addition of V, Cr or Ni, the improvement was the highest when Cr was used. The order of the ductility was as follows: Fe8CrAl7 > Fe8NiAl7 > Fe8VAl7 > Fe8Al8. The results of electronic structure analysis showed that FeAl were brittle, mainly due to the orbital hybridization of the s, p and d state electron of Fe and the s and p state electrons of Al, showing typical characteristics of a valence bond. Micro-mechanism for improving ductility of FeAl is that d orbital electron of alloying element is maily involved in hybridization of FeAl, alloying element V, Cr and Ni decrease the directional property in bonding of FeAl.

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First-Principles Calculation of Conductivity of Ce-C Codoped SnO2 Contacts

Advances in Condensed Matter Physics ◽

10.1155/2021/4346979 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Can Ding ◽

Zhenjiang Gao ◽

Xing Hu ◽

Zhao Yuan

Keyword(s):

Charge Density ◽

Lattice Constant ◽

First Principles ◽

Density Functional ◽

Energy Levels ◽

Circuit Breaker ◽

Enthalpy Change ◽

First Principles Calculation ◽

Contact Material ◽

Electronic Density

The contact is the core element of the vacuum interrupter of the mechanical DC circuit breaker. The electrical conductivity and welding resistance of the material directly affect its stability and reliability. AgSnO2 contact material has low resistivity, welding resistance, and so on. This material occupies an important position of the circuit breaker contact material. This research is based on the first-principles analysis method of density functional theory. The article calculated the lattice constant, enthalpy change, energy band, electronic density of state, charge density distribution, population, and conductivity of Ce, C single-doped, and Ce-C codoped SnO2 systems. The results show that Ce, C single doping, and Ce-C codoping all increase the cell volume and lattice constant. When the elements are codoped, the enthalpy change is the largest, and the thermal stability is the best. It has the smallest bandgap, the most impurity energy levels, and the least energy required for electronic transitions. The 4f orbital electrons of the Ce atom and the 2p orbital electrons of C are the sources of impurity energy near the Fermi level. When the elements are codoped, more impurity energy levels are generated at the bottom of the conduction band and the top of the valence band. Its bandgap is reduced so conductivity is improved. From the charge density and population analysis, the number of free electrons of Ce atoms and C atoms is redistributed after codoping. It forms a Ce-C covalent bond to further increase the degree of commonality of electrons and enhance the metallicity. The conductivity analysis shows that both single-doped and codoped conductivity have been improved. When the elements are codoped, the conductivity is the largest, and the conductivity is the best.

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Possidle Isomers and Electronic Structure of C60H36

MRS Proceedings ◽

10.1557/proc-206-687 ◽

1990 ◽

Vol 206 ◽

Cited By ~ 3

Author(s):

B. I. Dunlap ◽

D. W. Brenner ◽

R. C. Mowrey ◽

J. W. Mintmire ◽

D. H. Robertson ◽

...

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Local Density ◽

High Symmetry ◽

Hydrogen Atoms ◽

Functional Methods ◽

Metastable Structure ◽

Total Energies ◽

Rice University

ABSTRACTNewly developed empirical hydrocarbon potentials and self-consistent first-principles local density functional methods are used to investigate possible isomers and the electronic structure of C60H36. Within the high symmetry Th structure conjectured by the groups at Rice University there are two inequivalent sets of hydrogen atoms containing twelve and twenty-four atoms respectively. Binding each set either inside or outside of the C60 cage leads to four isomers of C60H36 with inequivalent strain energies. Although we find that placing twelve hydrogens inside the cage can lead to a metastable structure, our calculated total energies suggest that the isomer with all the hydrogens on the outside of the cage is the energetically most stable.

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The Influence of Electronic Structure Modelling and Junction Structure on First-Principles Chiral Induced Spin Selectivity

10.26434/chemrxiv.12497690 ◽

2020 ◽

Author(s):

Martin Sebastian Zöllner ◽

Vladimiro Mujica ◽

Carmen Herrmann

Keyword(s):

Electronic Structure ◽

First Principles ◽

Density Functional ◽

Orbit Coupling ◽

First Principles Calculation ◽

Physical Parameters ◽

Theory Approach ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Junction Structure

<br>We have carried out a comprehensive study of the influence of electronic structure modeling and junction structure description on the first-principles calculation of the spin polarization in molecular junctions caused by the chiral induced spin selectivity (CISS) effect. We explore the limits and the sensitivity to modelling decisions of a Landauer / Green’s function / density functional theory approach to CISS. We find that although the CISS effect is entirely attributed in the literature to molecular spin filtering, spin-orbit coupling being partially inherited from the metal electrodes plays an important role in our calculations, even though this effect cannot explain the experi- mental conductance results. Also, an important dependence on the specific description of exchange interaction and spin–orbit coupling is manifest in our approach. This is important because the interplay between exchange effects and spin-orbit coupling may play an important role in the description of the junction magnetic response. Our calculations are relevant for the whole field of spin-polarized electron transport and electron transfer because there is still an open discussion in the literature about the detailed underlying mechanism and the magnitude of relevant physical parameters that need to be included to achieve a consistent description of the CISS effect<br>

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Theoretical Investigation on Microstructure of the Novel 24R-Type LPSO Phase in Mg97Zn1Y2 Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.233-235.2359 ◽

2011 ◽

Vol 233-235 ◽

pp. 2359-2366

Author(s):

Ping Ying Tang ◽

Meng Xue Zeng ◽

Dong Lin Li ◽

Bi Yu Tang ◽

Li Ming Peng ◽

...

Keyword(s):

First Principles ◽

Density Functional ◽

Stacking Fault ◽

First Principles Calculation ◽

The Novel ◽

Ordered Structure ◽

Density Of State ◽

Electronic Density ◽

Functional Theory ◽

Long Period

The first-principles calculation based on density functional theory has been carried out to study the microstructural feature of the novel 24R-type long period stacking ordered structure in Mg97Zn1Y2alloy. The lattice positions of the Y and Zn atoms are determined theoretically, it is shown that the additive atoms are firstly enriched in the stacking fault layers at the two ends, a small amount are distributed in the interior stacking fault layers of the structure. And the arrangement of these Y and Zn atoms trends to be along the diagonal line of the unit cell. The structural stability is analyzed and the electronic density of state is discussed as well as.

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Electronic structure and optical properties of CsI under high pressure: a first-principles study

RSC Advances ◽

10.1039/c7ra08777b ◽

2017 ◽

Vol 7 (83) ◽

pp. 52449-52455 ◽

Cited By ~ 6

Author(s):

Qiang Zhao ◽

Zheng Zhang ◽

Xiaoping Ouyang

Keyword(s):

Density Functional Theory ◽

High Pressure ◽

Optical Properties ◽

Electronic Structure ◽

First Principles ◽

Calculation Method ◽

Density Functional ◽

First Principles Calculation ◽

Functional Theory ◽

First Principles Study

We investigated the effects of high pressure on the electronic structure and optical properties of a CsI crystal through a first-principles calculation method based on density functional theory.

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Electronic Structure and Ground State Properties of A4[Ag4O4] (A=Na, K and Rb): A First-Principles Study

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.665.43 ◽

2013 ◽

Vol 665 ◽

pp. 43-48

Author(s):

Rajagopalan Umamaheswari ◽

M. Yogeswari ◽

G. Kalpana

Keyword(s):

Electronic Structure ◽

Band Gap ◽

Ground State ◽

First Principles ◽

Density Functional ◽

Electronic Band Structure ◽

First Principles Calculation ◽

Partial Density ◽

Electronic Band ◽

Ground State Properties

The first-principles calculation within density functional theory is used to study in detail the electronic structure and ground state properties of alkali-metal oxoargenates A4[Ag4O4] (A= Na, K and Rb). The total energies calculated within the atomic sphere approximation (ASA) were used to determine the ground state properties such as equilibrium lattice parameter, c/a ratio, bulk modulus and cohesive energy. The theoretically calculated equilibrium lattice constants values are in well agreement with the available experimental values. The electronic band structures, total and partial density of states are calculated. The result of electronic band structure shows that the KAgO and RbAgO are direct band gap semiconductors with their gap lying between the Γ-Γ points, whereas NaAgO is found to be an indirect band gap semiconductor with its gap lying between Z-Γ points.

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First Principles Calculations Study of Lithium-Montmorillonite for Humidity Sensor Application

KnE Engineering ◽

10.18502/keg.v1i1.490 ◽

2016 ◽

Vol 1 ◽

Cited By ~ 1

Author(s):

Triati Dewi Kencana Wungu

Keyword(s):

Electronic Structure ◽

Water Molecule ◽

First Principles ◽

Density Functional ◽

Humidity Sensor ◽

Point Of View ◽

First Principles Calculation ◽

Repulsive Interaction ◽

Hydrogen Atoms ◽

Sensor Application

In this study, we performed calculations on the water molecule adsorbed on lithium montmorillonite using first principles-calculation by means of electronic-structure calculation, with emphasis on approaches based on Density Functional Theory (DFT). The mechanism of water molecule adsorption on the surface of lithium-montmorillonite was investigated from the electronic structure point of view to seek the possibility of using montmorillonite as humidity sensor. The effects of the Van der Waals force to the electronic properties of water molecule on the surface of montmorillonite was also considered and obtained that the structure is more stable energetically. The interaction of water molecule with surface of montmorillonite yields the rotation of the hydrogen atoms of water molecule due to the occurrence of repulsive interaction between two positive ions of hydrogen of water molecule and lithium. From the calculations, lithium-montmorillonite can be considered as a good material for humidity sensor application since there is an electrical change observed even though it is a relatively small that is 0.657 eV.

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Electronic structure and phase stability of In-free photovoltaic semiconductors, Cu2ZnSnSe4 and Cu2ZnSnS4 by first-principles calculation

MRS Proceedings ◽

10.1557/proc-1165-m04-03 ◽

2009 ◽

Vol 1165 ◽

Cited By ~ 34

Author(s):

Tsuyoshi Maeda ◽

Satoshi Nakamura ◽

Takahiro Wada

Keyword(s):

Electronic Structure ◽

Plane Wave ◽

Phase Stability ◽

First Principles ◽

Density Functional ◽

Formation Enthalpy ◽

First Principles Calculation ◽

Enthalpies Of Formation ◽

Functional Formalism ◽

The Difference

AbstractWe have theoretically evaluated the phase stability and electronic structure of Cu2ZnSnSe4 (CZTSe) and Cu2ZnSnS4 (CZTS). The enthalpies of formation for kesterite, stannite and wurtz-stannite phases of CZTSe and CZTS were calculated using a plane-wave pseudopotential method within the density functional formalism. For CZTSe, the calculated formation enthalpy (ΔH) of the kesterite phase (−312.7 kJ/mol) is a little smaller than that of the stannite phase (−311.3 kJ/mol) and much smaller than that of the wurtz-stannite phase (−305.7 kJ/mol). For CZTS, the ΔH of the kesterite phase (−361.9 kJ/mol) is smaller than that of the stannite phase (−359.9 kJ/mol) and much smaller than that of the wurtz-stannite phase (−354.6 kJ/mol). The difference of ΔH between the kesterite and stannite phases for CZTS is greater than that for CZTSe. This indicates the kesterite phase is more stable than the stannite phase in CZTS compared with CZTSe. The valence band maximums (VBMs) of both the kesterite- and stannite-type CZTSe(CZTS) are antibonding orbitals of Cu 3d and Se 4p (S 3p). The conduction band minimums (CBMs) are antibonding orbitals of Sn 5s and Se 4p (S 3p). The Zn atom does not affect the VBM or the CBM in either CZTSe(CZTS). The theoretical band gap of the kesterite phase calculated with sX-LDA in both CZTSe and CZTS is a little wider than that of the wurtz-stannite phase and much wider than that of the stannite phase.

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First-principles calculations of magnetic and mechanical properties of Fe-based nanocrystalline alloy Fe80Si10Nb6B2Cu2

Applied Mathematics and Nonlinear Sciences ◽

10.2478/amns.2021.2.00109 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Chong Sun ◽

Zhengang Shi ◽

Wenjie Fu ◽

Linhao Zhang ◽

Han Li ◽

...

Keyword(s):

Band Structure ◽

Magnetic Moment ◽

First Principles ◽

Density Functional ◽

Energy Gap ◽

Population Analysis ◽

Decisive Role ◽

Nanocrystalline Alloy ◽

State Density ◽

First Principles Calculation

Abstract Based on the first-principles calculation method of density functional theory (DFT), the crystal structure, band structure, magnetic moment, density of state, elastic constant and population analysis of Fe80Si10Nb6B2Cu2 are calculated. The calculation results show that the Fe-based nanocrystalline alloy of this composition has a stable structure, strong resistance to deformation, high hardness and is an alloy with good flexibility. The energy band structure of spin-up and spin-down is basically the same, and the energy gap is 0 eV, showing metallicity. The asymmetry of the electronic state density between the spin-up and spin-down states indicates that the alloy is ferromagnetic, with a magnetic moment of 84.15 μ; the Fe element plays a decisive role in the magnetic properties of this alloy.

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