Temperature effects on the universal equation of state of solids

Vinet, Pascal; Smith, J. R.; Ferrante, John; Rose, James H.

doi:10.1103/physrevb.35.1945

Cited by 526 publications

(367 citation statements)

References 30 publications

Supporting

Mentioning

347

Contrasting

Order By: Relevance

“…In practice, the energy E(V ) is approximated (via least square fit) by the Rose-Vinet equation of state 22 , which allows for an accurate numerical differentiation. For GGA, we were unable to find a single Rose-Vinet fit which would be accurate in both GPa and TPa pressure ranges, therefore we had to use two different parametrizations.…”

Section: B Elasticity Under Initial Pressurementioning

confidence: 99%

Elastic anisotropy and Poisson's ratio of solid helium under pressure

et al. 2015

View full text Add to dashboard Cite

The elastic moduli, elastic anisotropy coefficients, sound velocities and Poisson's ratio of hcp solid helium have been calculated using density functional theory in generalized gradient approximation (up to 30 TPa), and pair+triple semi-empirical potentials (up to 100 GPa). Zero-point vibrations have been treated in the Debye approximation assuming 4 He isotope (we exclude the quantumcrystal region at very low pressures from consideration). Both methods give a reasonable agreement with the available experimental data. Our calculations predict significant elastic anisotropy of helium (△P ≈ 1.14, △S1 ≈ 1.7, △S2 ≈ 0.93 at low pressures). Under terapascal pressures helium becomes more elastically isotropic. At the metallization point there is a sharp feature in the elastic modulus CS, which is the stiffness with respect to the isochoric change of the c/a ratio. This is connected with the previously obtained sharp minimum of the c/a ratio at the metallization point.Our calculations confirm the previously measured decrease of the Poisson's ratio with increasing pressure. This is not a quantum effect, as the same sign of the pressure effect was obtained when we disregarded zero-point vibrations. At TPa pressures Poisson's ratio reaches the value of 0.31 at the theoretical metallization point (V mol = 0.228 cm 3 /mol, p = 17.48 TPa) and 0.29 at 30 TPa. For p = 0 we predict a Poisson's ratio of 0.38 which is in excellent agreement with the low-p-low-T experimental data.

show abstract

Section: B Elasticity Under Initial Pressurementioning

confidence: 99%

Elastic anisotropy and Poisson's ratio of solid helium under pressure

et al. 2015

View full text Add to dashboard Cite

show abstract

“…We were able to represent our zero-temperature static lattice GGA pressure data in the insulating regime by a Vinet EOS curve [25] with the parameters V 0 = 20.6397 cm 3 /mol as zero-pressure volume, B 0 = 0.01928 GPa as bulk modulus, and B ′ 0 = 9.2153 as its derivative. The fit reproduced our GGA data from 3 to 1200 GPa with an accuracy of 3%.…”

mentioning

confidence: 99%

First-Principles Studies of the Metallization and the Equation of State of Solid Helium

Khairallah

Militzer

2008

Phys. Rev. Lett.

View full text Add to dashboard Cite

The insulator-to-metal transition in solid helium at high pressure is studied with first-principles simulations. Diffusion quantum Monte Carlo (DMC) calculations predict that the band gap closes at a density of 21.3 g/cm 3 and a pressure of 25.7 terapascals, which is 20% higher in density and 40% higher in pressure than predicted by density functional calculations based on the generalized gradient approximation (GGA). The metallization density derived from GW calculations is found to be in very close agreement with DMC predictions. The zero point motion of the nuclei had no effect on the metallization density within the accuracy of the calculation. Finally, fit functions for the equation of state are presented and the magnitude of the electronic correlation effects left out of the GGA approximation are discussed.

show abstract

“…In general, the use of such a linearized and inverted EoS has some advantages in the application of parametric refinements, as in contrast to other EoS, like the Birch-Murnaghan EoS [29] or the Vinet EoS [30], which are normally expressed as P(V) relations, the Murnaghan EoS can be analytically inverted and in doing so it gives direct access to a volume on pressure dependence 1 . Although the volume is not a directly refineable parameter, further linearization can be done, to get the dependence of the lattice parameter on pressure.…”

Section: Parametric Rietveld Refinementmentioning

confidence: 99%

Possibilities and limitations of parametric Rietveld refinement on high pressure data: The case study of LaFeO3

Dinnebier

Etter

Müller

et al. 2014

Zeitschrift Für Kristallographie Crystalline Materials

View full text Add to dashboard Cite

Parametric Rietveld refinement is a powerful technique to apply directly physical or empirical equations to the refinement of in situ powder diffraction data. In order to investigate the possibilities and limitations of parametric Rietveld refinements for high pressure data four competitive crystallographic approaches were used to carry out a full structural investigation of the orthoferrite LaFeO 3 (Pbnm at ambient conditions) under high pressure up to 47 GPa. Approach A with traditional Rietveld refinement using atomic coordinates, Approach B where the Rietveld refinement was done by using the rigid body method, Approach C where symmetry modes were used and Approach D where the newly developed method of the rotational symmetry mode description for a rigid body was used. For all approaches sequential as well as parametric refinements were carried out, confirming a second order phase transition of LaFeO 3 to a higher symmetric phase (space group Ibmm) at around 21.1 GPa and an isostructural first order phase transition at around 38 GPa. Limitations due to non-hydrostatic conditions as well as the possibilities of a direct modeling of phase transitions with parametric Rietveld refinement are discussed in detail.

show abstract

Temperature effects on the universal equation of state of solids

Cited by 526 publications

References 30 publications

Elastic anisotropy and Poisson's ratio of solid helium under pressure

Elastic anisotropy and Poisson's ratio of solid helium under pressure

First-Principles Studies of the Metallization and the Equation of State of Solid Helium

Possibilities and limitations of parametric Rietveld refinement on high pressure data: The case study of LaFeO3

Contact Info

Product

Resources

About