First-principles thermoelasticity of bcc iron under pressure

First-principles thermoelasticity of bcc iron under pressure

We investigate the elastic and isotropic aggregate properties of ferromagnetic bcc iron as a function of temperature and pressure by computing the Helmholtz free energies for the volume-conserving strained structures using the first-principles linear response linear-muffin-tin-orbital method and the generalized-gradient approximation. We include the electronic excitation contributions to the fr...

Lattice dynamics and thermodynamics of bcc iron under pressure: First-principles linear response study

We compute the lattice-dynamical and thermal equation of state properties of ferromagnetic bcc iron using the first-principles linear response linear-muffin-tin-orbital method in the generalized-gradient approximation. The calculated phonon dispersion and phonon density of states, both at ambient and high pressures, show good agreement with inelastic neutron scattering data. We find the free en...

First Principles Quasiharmonic Thermoelasticity of Mantle Minerals

Thermodynamic (Anderson 2005) and elastic properties (Musgrave 1970) of minerals provide the fundamental information needed to analyze seismic observations and to model Earth’s dynamic state. The connection between pressure, temperature, chemical composition, and mineralogy that produce seismic velocity gradients, heterogeneities, and discontinuities, can be established with knowledge of thermo...

First Principles Study of Tetracene under Pressure

First-principles study of CaFe2As2 under pressure

We perform first-principles calculations on CaFe2As2 under hydrostatic pressure. Our total-energy calculations show that though the striped antiferromagnetic (AFM) orthorhombic (OR) phase is favored at P = 0, a nonmagnetic collapsed tetragonal (cT) phase with diminished c parameter is favored for P > 0.36 GPa, in agreement with experiments. Rather than a mechanical instability, this is an entha...