First-principles investigation of novel polymorphs of Mg2C

The structural competing and atomic ordering of the full Heusler compounds Fe 2 NiSi and Ni 2 FeSi under uniform and tetragonal strains have been systematically studied by the first-principles calculation. Both Fe 2 NiSi and Ni 2 FeSi have the XA structure in cubic phase and they show metallic band structures and large magnetic moments (greater than 3 μ B ) at equilibrium condition. Tetragonal distortion can further decrease the total energy, leading to the possible phase transformation. Furthermore, different atom reordering behaviours have been observed: for Fe 2 NiSi, atoms reorder from cubic XA-type to tetragonal L1 0 -type; for Ni 2 FeSi, there is only structural transformation without atom reordering. The total magnetic moments of Fe 2 NiSi and Ni 2 FeSi are mainly contributed by Fe atoms, and Si atom can strongly suppress the moments of Fe atoms when it is present in the nearest neighbours of Fe atoms. With the applied strain, the distance between Fe and Si atoms play an important role for the magnetic moment variation of Fe atom. Moreover, the metallic band nature is maintained for Fe 2 NiSi and Ni 2 FeSi under both uniform and tetragonal strains. This study provides a detailed theoretical analysis about the full Heusler compounds Fe 2 NiSi and Ni 2 FeSi under strain conditions.

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First-principles calculations of the single-bonded cubic phase of nitrogen

Physical Review B ◽

10.1103/physrevb.73.012101 ◽

2006 ◽

Vol 73 (1) ◽

Cited By ~ 13

Author(s):

H. L. Yu ◽

G. W. Yang ◽

X. H. Yan ◽

Y. Xiao ◽

Y. L. Mao ◽

...

Keyword(s):

First Principles ◽

Cubic Phase ◽

First Principles Calculations

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High-Pressure Properties of Na3ClO Anti-perovskite from First Principles: an exploratory study

MRS Proceedings ◽

10.1557/proc-499-167 ◽

1997 ◽

Vol 499 ◽

Cited By ~ 2

Author(s):

A. V. G. Chizmeshya ◽

O. F. Sankey ◽

P. F. McMillan

Keyword(s):

First Principles ◽

Theoretical Study ◽

Ambient Pressure ◽

Lattice Energy ◽

Cubic Phase ◽

Compression Behavior ◽

Symmetry Structure ◽

Flapw Method ◽

Static Lattice ◽

The Ideal

ABSTRACTWe present the results of an exploratory theoretical study of Na3ClO in the anti-perovskite structure. The FLAPW method is used to calculate the static lattice properties, pressure equation of state, and the ferroic Flu phonon frequencies in the cubic PmSm phase. We also compute the compression behavior of NaCl and Na2O and find that the lattice energy of Na3ClO at ambient pressure (static lattice) is only marginally larger than of products, in agreement with experiment. However, detailed calculations reveal M- and R-point phonon instabilities in the ideal cubic phase and suggest the existence of lower symmetry structure involving slight rotations of ONa6 octahedra.

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First principles study of structural and electronic properties of cubic phase of ZrO2 and HfO2

Physica B Condensed Matter ◽

10.1016/j.physb.2013.10.037 ◽

2014 ◽

Vol 434 ◽

pp. 7-13 ◽

Cited By ~ 26

Author(s):

Yong-Liang Yang ◽

Xiao-Li Fan ◽

Chong Liu ◽

Run-Xin Ran

Keyword(s):

Electronic Properties ◽

First Principles ◽

Cubic Phase ◽

First Principles Study ◽

Structural And Electronic Properties

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First-principles study of A7 to simple cubic phase transformation in As

Physica B Condensed Matter ◽

10.1016/j.physb.2007.06.015 ◽

2007 ◽

Vol 400 (1-2) ◽

pp. 22-25 ◽

Cited By ~ 6

Author(s):

Wenxia Feng ◽

Shouxin Cui ◽

Haiquan Hu ◽

Hong Liu

Keyword(s):

Phase Transformation ◽

First Principles ◽

Cubic Phase ◽

First Principles Study ◽

Simple Cubic

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Phonon density of states of model ferroelectrics

MRS Proceedings ◽

10.1557/proc-1262-w01-02 ◽

2010 ◽

Vol 1262 ◽

Author(s):

Narayani Choudhury ◽

Alexander I Kolesnikov ◽

Helmut Schober ◽

Eric J Walter ◽

Mark Johnson ◽

...

Keyword(s):

Density Of States ◽

First Principles ◽

Density Functional ◽

Inelastic Neutron Scattering ◽

Inelastic Neutron ◽

Cubic Phase ◽

Phonon Density ◽

Phonon Density Of States ◽

Phonon Spectra ◽

Quantum Paraelectric

AbstractFirst principles density functional calculations and inelastic neutron scattering measurements have been used to study the variations of the phonon density of states of PbTiO3 and SrTiO3 as a function of temperature. The phonon spectra of the quantum paraelectric SrTiO3 is found to be fundamentally distinct from those of ferroelectric PbTiO3 and BaTiO3. SrTiO3 has a large 70-90 meV phonon band-gap in both the low temperature antiferrodistortive tetragonal phase and in the high temperature cubic phase.Key bonding changes in these perovskites lead to spectacular differences in their observed phonon density of states.

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