scholarly journals Enhanced polarization in strained BaTiO3 from first principles

2002 ◽  
Vol 718 ◽  
Author(s):  
J. B. Neaton ◽  
C.-L. Hsueh ◽  
K. M. Rabe
Keyword(s):  
Thin Films ◽  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Berry Phase ◽  
Local Density ◽  
Misfit Strain ◽  
Density Approximation ◽  
Functional Theory ◽  
Tetragonal Batio

AbstractThe structure, polarization, and zone-center phonons of bulk tetragonal BaTiO3 under compressive epitaxial stress are calculated using density functional theory within the local density approximation. The polarization, computed using the Berry-phase formalism, increases with increasing tetragonality and is found to be enhanced by nearly 70% for the largest compressive misfit strain considered (-2.28%). The results are expected to be useful for the analysis of coherent epitaxial BaTiO3 thin films and heterostructures grown on perovskite substrates having a smaller lattice constant, such as SrTiO3.

First-principles Calculations of Energetic Properties of Vacancies, Mn-atomic Defects in CdTe

2006 ◽  
Vol 959 ◽  
Author(s):  
Ghouti Merad ◽  
Benali Rerbal ◽  
Hafid Aourag ◽  
Joël Cibert
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Density Approximation ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Energetic Properties ◽  
Atomistic Modelling ◽  
Atomic Type

ABSTRACTAn atomistic modelling based on density functional theory within the framework of the local density approximation is used to show the trends in the energetic properties of single and double defects in CdTe semiconductor, without phase transformation. A systematic study of vacancies, Mn substituting Cd atoms in a supercell structure consisting of 16-atoms is presented. The changes of structural properties and lattice parameters due to the addition of Mn-atomic type defects in CdTe matrix are compared, and the number of vacancies is also determined from the total energy calculations.

First-principles study of electronic and optical properties of solid-solution ZnO1−xSx

2017 ◽  
Vol 31 (23) ◽  
pp. 1750175 ◽  
Author(s):  
Margi Jani ◽  
Abhijit Ray
Keyword(s):  
Solid Solution ◽  
Density Functional Theory ◽  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Density Approximation ◽  
Functional Theory ◽  
Electronic And Optical Properties ◽  
Strong Localization

We investigated the electronic and optical properties of ZnO under the circumstances of isovalent anionic doping by sulfur. A pseudopotential implementation of density functional theory is applied within the local density approximation to examine the modification of band structure in wurtzite ZnO by sulfur substitution. Although Fermi level position does not change, a strong localization of Zn-[Formula: see text] orbital is found by S-doping. Optical properties and constants are found to strongly depend on the sulfur content at low photon energies.

Thermodynamic properties of ZnTe in zinc-blende and wurtzite phases

2016 ◽  
Vol 30 (21) ◽  
pp. 1650147 ◽  
Author(s):  
S. Ferahtia ◽  
S. Saib ◽  
N. Bouarissa
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Density Approximation ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
Two Phases

The present study deals with first-principles calculations of the thermal properties of ZnTe in the two phases namely, zinc-blende and wurtzite. The calculations are mainly performed using the density functional theory with the local density approximation and response-function calculations. The full phonon dispersions throughout the Brillouin zone are presented. The temperature dependence of the lattice parameters, bulk modulus, entropy and heat capacity are examined and discussed. Our findings agree reasonably well with those available in the literature.

First-Principles Study on the Electronic Structure of N-Doped Orthorhombic SrHfO3

2011 ◽  
Vol 239-242 ◽  
pp. 1231-1234
Author(s):  
Qi Jun Liu ◽  
Zheng Tang Liu ◽  
Li Ping Feng ◽  
Hao Tian
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Charge Transfer ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Density Approximation ◽  
Functional Theory ◽  
Bonding Properties ◽  
Valence Bands

The electronic properties of N-doped orthorhombic SrHfO3 have been calculated using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory with the local density approximation. From the calculated band structure and density of states, the bandgap reduction is observed due to the presence of the N-2p states in the top of valence bands, which leads to red-shift. Moreover, in order to clarify the charge transfer and bonding properties of N-doped orthorhombic SrHfO3, we have calculated and analysed the charge density.

TIME-DEPENDENT DENSITY FUNCTIONAL STUDY OF MULTIELECTRON TRANSFER IN Cq+–Na4 COLLISIONS

2010 ◽  
Vol 24 (24) ◽  
pp. 4811-4820
Author(s):  
Y. P. ZHANG ◽  
F. S. ZHANG ◽  
Y. GAO ◽  
H. W. CHANG ◽  
G. Q. XIAO
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Local Density ◽  
Time Dependent ◽  
Functional Study ◽  
Density Approximation ◽  
Functional Theory ◽  
The Difference ◽  
Multielectron Transfer ◽  
Dependent Density

The process of multielectron transfer from a Na 4 cluster induced by highly charged C 6+, C 4+, C 2+ and C + ions is studied using the method of time-dependent density functional theory within the local density approximation combined with the use of pseudopotential. The evolution of dipole moment changes and emitted electrons in Na 4 is obtained and the time-dependent probabilities with various charges are deduced. It is shown that the Na 4 cluster is strongly ionized by C 6+ and that the number of emitted electrons per atom of Na 4 is larger than that of Na 2 under the same condition. One can find that the detailed information of the emitted electrons from Na 4 is different from the same from Na 2, which is possibly related to the difference in structure between the two clusters.

scholarly journals First-Principles Determination of the Polarizabilities of Carbon Tubules as a Function of Length

1994 ◽  
Vol 349 ◽  
Author(s):  
Andrew A. Quong ◽  
Mark R. Pederson
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Valence Electron ◽  
Local Density ◽  
Density Approximation ◽  
Functional Theory ◽  
Size Dependent ◽  
The Density Functional Theory ◽  
Linear And Nonlinear

ABSTRACTWe use the local-density-approximation to the density-functional theory to determine the axial polarizabilities of fullerene tubules as a function of length and winding topologies. Specifically, we present linear polarizabilities for tubules of composition C12H24, C36H24, C40H20 and C60H24. The size-dependent variation in the dipole-coupled gaps between pairs of occupied and unoccupied levels leads to enhancements in the polarizability per valence electron as the length of the tubule increases. The results are compared to recent densityfunctional based calculations of the linear and nonlinear polarizabilities for fullerene and benzene molecules.

Study of Thermodynamic Properties of Superhard w-BC2N

2013 ◽  
Vol 750-752 ◽  
pp. 1141-1145
Author(s):  
Ai Ling Ding ◽  
Feng Li ◽  
Chun Mei Li ◽  
Jing Ao ◽  
Zhi Qian Chen
Keyword(s):  
Density Functional Theory ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Local Density ◽  
Density Functional Theory Method ◽  
Debye Model ◽  
Theory Method ◽  
Density Approximation ◽  
Functional Theory

We investigate the thermodynamic properties of superhard w-BC2N by using ab initio plane-wave pseudopotential density functional theory method within local density approximation (LDA). Through the quasi-harmonic Debye model, we investigate the thermodynamic properties of w-BC2N. The variation of the thermal expansion, the heat capacity and the Gruneisen parameter γ with pressure P and temperature T, and many other thermodynamic parameters of w-BC2N are obtained systematically.

ELECTRONIC AND DYNAMICAL PROPERTIES OF MgB2 AND RELATED COMPOUNDS

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1563-1569 ◽  
Author(s):  
G. PROFETA ◽  
A. CONTINENZA ◽  
F. BERNARDINI ◽  
G. SATTA ◽  
S. MASSIDDA
Keyword(s):  
Density Functional Theory ◽  
Local Density Approximation ◽  
Density Functional ◽  
Local Density ◽  
Density Approximation ◽  
Superconducting Properties ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Dynamical Properties ◽  
Related Compounds

We report a detailed study of the electronic and dynamical properties of MgB2 , BeB2 and of the AlMgB4 superlattice, within the local density approximation to the density functional theory. On the basis of our results we discuss the superconducting properties of these systems, and point to the high T c in MgB2 as a fortunate combination of events.

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