Abstract
A first-principles approach called the self-consistent quasiharmonic approximation (SC-QHA) method is formulated to calculate the thermal expansion, thermomechanics, and thermodynamic functions of solids at finite temperatures with both high efficiency and accuracy. The SC-QHA method requires fewer phonon calculations than the conventional QHA method, and also facilitates the convenient analysis of the microscopic origins of macroscopic thermal phenomena. The superior performance of the SC-QHA method is systematically examined by comparing it with the conventional QHA method and experimental measurements on silicon, diamond, and alumina. It is then used to study the effects of pressure on the anharmonic lattice properties of diamond and alumina. The thermal expansion and thermomechanics of Ca3Ti2O7, which is a recently discovered important ferroelectric ceramic with a complex crystal structure that is computationally challenging for the conventional QHA method, are also calculated using the formulated SC-QHA method. The SC-QHA method can significantly reduce the computational expense for various quasiharmonic thermal properties especially when there are a large number of structures to consider or when the solid is structurally complex. It is anticipated that the algorithm will be useful for a variety of fields, including oxidation, corrosion, high-pressure physics, ferroelectrics, and high-throughput structure screening when temperature effects are required to accurately describe realistic properties.
Original language | English (US) |
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Pages (from-to) | 84-93 |
Number of pages | 10 |
Journal | Computational Materials Science |
Volume | 120 |
DOIs | |
State | Published - Jul 1 2016 |
Funding
L.-F.H. and J.M.R. wish to thank Dr. M. Senn (University of Oxford), and Prof. S.-W. Cheong (Rutgers University) for providing additional experimental data for Ca 3 Ti 2 O 7 , as well as for the helpful e-mail exchanges. L.-F.H. and E.T. were supported by the Office of Naval Research MURI “Understanding Atomic Scale Structure in Four Dimensions to Design and Control Corrosion Resistant Alloys” under Grant No. N00014-14-1-0675 . X.-Z.L. and J.M.R. were supported by the National Science Foundation (NSF) through the Pennsylvania State University MRSEC under award number DMR-1420620 . Calculations were performed using the QUEST HPC Facility at Northwestern University and the HPCMP facilities at the Navy DoD Supercomputing Resource center.
Keywords
- Density functional theory
- Quasiharmonic approximation
- Thermal expansion
- Thermomechanics
ASJC Scopus subject areas
- General Computer Science
- General Chemistry
- General Materials Science
- Mechanics of Materials
- General Physics and Astronomy
- Computational Mathematics