scholarly journals Development of Basic Technologies for the DAC, Study of Structural Phase Transitions of the Elements, and Determination of Equation of States

2012 ◽  
Vol 22 (2) ◽  
pp. 135-143
Author(s):  
TAKEMURA Kenichi
Keyword(s):  
Phase Transitions ◽  
Structural Phase ◽  
Structural Phase Transitions ◽  
Equation Of States

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.

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

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

Structural phase transitions of LaScO3 from first principles

2021 ◽  
Vol 26 ◽  
pp. 102048
Author(s):  
Craig A.J. Fisher ◽  
Ayako Taguchi ◽  
Takafumi Ogawa ◽  
Akihide Kuwabara
Keyword(s):  
Phase Transitions ◽  
First Principles ◽  
Structural Phase ◽  
Structural Phase Transitions

scholarly journals The origin of the lattice thermal conductivity enhancement at the ferroelectric phase transition in GeTe

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Đorđe Dangić ◽  
Olle Hellman ◽  
Stephen Fahy ◽  
Ivana Savić
Keyword(s):  
Phase Transition ◽  
Thermal Conductivity ◽  
Phase Transitions ◽  
Thermoelectric Materials ◽  
Ferroelectric Phase Transition ◽  
Lattice Thermal Conductivity ◽  
Ferroelectric Phase ◽  
Structural Phase ◽  
High Symmetry ◽  
Structural Phase Transitions

AbstractThe proximity to structural phase transitions in IV-VI thermoelectric materials is one of the main reasons for their large phonon anharmonicity and intrinsically low lattice thermal conductivity κ. However, the κ of GeTe increases at the ferroelectric phase transition near 700 K. Using first-principles calculations with the temperature dependent effective potential method, we show that this rise in κ is the consequence of negative thermal expansion in the rhombohedral phase and increase in the phonon lifetimes in the high-symmetry phase. Strong anharmonicity near the phase transition induces non-Lorentzian shapes of the phonon power spectra. To account for these effects, we implement a method of calculating κ based on the Green-Kubo approach and find that the Boltzmann transport equation underestimates κ near the phase transition. Our findings elucidate the influence of structural phase transitions on κ and provide guidance for design of better thermoelectric materials.

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