TY - JOUR
T1 - Quasiharmonic thermal elasticity of crystals
T2 - An analytical approach
AU - Wu, Zhongqing
AU - Wentzcovitch, Renata M
PY - 2011/5/25
Y1 - 2011/5/25
N2 - First-principles quasiharmonic calculations play a very important role in mineral physics because they can predict the structural and thermodynamic properties of materials at pressure and temperature conditions of the Earth's interior that are still challenging for experiments. They also enable calculations of thermal elastic properties by providing second-order derivatives of free energies with respect to strain. The latter are essential to interpret seismic tomography of the mantle in terms of temperature, composition, and mineralogy, in the context of geophysical processes. However, these are exceedingly demanding computations requiring up to ∼103 parallel jobs running on tens or more processors each. Here we introduce an analytical and computationally simpler approach that requires only calculations of static elastic constants and phonon density of states for unstrained configurations. This approach, currently implemented for crystals with up to orthorhombic symmetry, decreases the computational effort, i.e., CPU time and human labor, by up to two orders of magnitude. Results for the major mantle phases periclase (MgO) and forsterite (α-Mg2SiO4) show excellent agreement with previous first-principles results and experimental data.
AB - First-principles quasiharmonic calculations play a very important role in mineral physics because they can predict the structural and thermodynamic properties of materials at pressure and temperature conditions of the Earth's interior that are still challenging for experiments. They also enable calculations of thermal elastic properties by providing second-order derivatives of free energies with respect to strain. The latter are essential to interpret seismic tomography of the mantle in terms of temperature, composition, and mineralogy, in the context of geophysical processes. However, these are exceedingly demanding computations requiring up to ∼103 parallel jobs running on tens or more processors each. Here we introduce an analytical and computationally simpler approach that requires only calculations of static elastic constants and phonon density of states for unstrained configurations. This approach, currently implemented for crystals with up to orthorhombic symmetry, decreases the computational effort, i.e., CPU time and human labor, by up to two orders of magnitude. Results for the major mantle phases periclase (MgO) and forsterite (α-Mg2SiO4) show excellent agreement with previous first-principles results and experimental data.
UR - http://www.scopus.com/inward/record.url?scp=79961158267&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79961158267&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.83.184115
DO - 10.1103/PhysRevB.83.184115
M3 - Article
AN - SCOPUS:79961158267
SN - 1098-0121
VL - 83
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 18
M1 - 184115
ER -