Pseudopotential Calculations of Structural Properties of Solids

1985 ◽  
Vol 63 ◽  
Author(s):  
Marvin L. Cohen
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Vibrational Properties ◽  
Structural Phase Transitions ◽  
Superconducting Properties ◽  
Lattice Constants ◽  
Pseudopotential Calculations ◽  
Pseudopotential Approach ◽  
Cohesive Energies

ABSTRACTThrough the development of a total energy pseudopotential approach, it has become possible to compute structural, electronic, and vibrational properties of solids using only the atomic numbers and atomic masses of the constituent atoms as input. The method has been applied to semiconductors, insulators, and metals; and agreement with experiment for most properties is usually within a few percent.Applications include the determination of lattice constants for specific structural phases, properties of structural phase transitions, cohesive energies, bulk moduli, lattice vibrational spectra, electron-lattice interaction parameters, and electronic and superconducting properties. A recent example is the prediction of superconductivity in highly condensed hexagonal silicon which was subsequently found experimentally.

STRUCTURAL PHASE TRANSITIONS AND MECHANICAL PROPERTIES OF OsO2 UNDER HIGH PRESSURE

2010 ◽  
Vol 24 (22) ◽  
pp. 4269-4279 ◽  
Author(s):  
YONGCHENG LIANG ◽  
ANHU LI ◽  
QIUHONG SONG
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Phase Transitions ◽  
First Principles ◽  
Structural Phase ◽  
Fluorite Phase ◽  
Structural Phase Transitions ◽  
Pseudopotential Calculations ◽  
Excellent Candidate ◽  
High Bulk

The structural phase transitions, mechanical properties and electronic structures of OsO 2 under high pressure are systemically investigated by the first-principles plane-wave basis pseudopotential calculations. The possible pressure-induced transition sequence in OsO 2 may be the rutile, pyrite and fluorite phases, and the stable CaCl 2 structure is not found. The fluorite phase has high bulk modulus (355.3 GPa), large shear modulus G (267.9 GPa), and huge elastic constant C44 (292.7 GPa), and consequently is an excellent candidate of superhard materials. Crystal structures, valence electron densities, band structures, DOS and PDOS of the rutile, pyrite and fluorite phases of OsO 2 have also been carefully analyzed to elucidate their mechanical properties.

scholarly journals Determination of the Nature of the Structural Phase Transitions in 122 Pnictide Systems

2012 ◽  
Vol 391 ◽  
pp. 012134
Author(s):  
J C Loudon ◽  
C J Bowell ◽  
J Gillett ◽  
S E Sebastian ◽  
P A Midgley
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Structural Phase Transitions

SELECTED PROPERTIES OF Y-Ba-Cu-O IN CONNECTION WITH THE PROPERTIES OF Cu-O CHAINS

1992 ◽  
Vol 06 (13) ◽  
pp. 2291-2319 ◽  
Author(s):  
G. UIMIN
Keyword(s):  
Phase Transitions ◽  
Lattice Gas ◽  
Structural Phase ◽  
Quantitative Interpretation ◽  
Structural Phase Transitions ◽  
Superconducting Properties ◽  
Chain Fragment ◽  
Formative Stage ◽  
Lattice Gas Models

Here we discuss some experimental evidence which supports a significant role of …-Cu-O…chain fragments, situated in oxygen deficient planes, in the doping of carriers into CuO 2 planes, in structural phase transitions and in many other normal and superconducting properties of Y-Ba-Cu-O . The relevant experiments are associated with the structural, magnetic, XAS, NMR/NQR investigations. The well-established phase diagram of YBa 2 Cu 3 O 6+x, i-e., the Néel, T N , and superconducting, T c , transition temperatures versus the oxygen content x, is the basis of the theory which should explain the structural phase transitions as well as the charge transfer mechanism. It appears that lattice-gas models do not answer all the requirements, particularly, concerned with the intrinsic chain fragments. Although the theory of the oxygen deficient plane, sharing quantum mechanics of finite chain fragments, statistical mechanics of the chain fragment ensemble as well as Monte Carlo simulations, is in its formative stage yet, it can readily apply to quantitative interpretation of selected experiments.

Phonons and magnons under the sequential structural phase transitions in La2NiO4

1991 ◽  
Vol 185-189 ◽  
pp. 895-896 ◽  
Author(s):  
S. Sugai ◽  
S. Hosoya ◽  
T. Kajitani ◽  
T. Fukuda ◽  
S. Onodera
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Structural Phase Transitions
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