2015/10/31 by Chee Kwan Gan, Jian Rui Soh, Yun Liu · 35 citations
Chemistry · Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Anharmonicity #Anisotropy #Chemistry #Condensed matter physics #Crystallography #Diffraction #High-pressure geophysics and materials #Inorganic Chemistry and Materials #Mathematical physics #Negative thermal expansion #Orthorhombic crystal system #Physics #Quantum mechanics #Thermal Expansion and Ionic Conductivity #Thermal expansion #Thermodynamics #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.92.235202
published in Physical Review B 92(23) (American Physical Society) · 4 pages, 4 figures
openalex publication_date 2015/12/02 · arxiv created 2015/12/12 · arxiv updated 2015/12/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We derive a compact matrix expression for the linear thermal expansion coefficients (TECs) for a general orthorhombic system which relates elastic properties and integrated quantities based on deformation and mode dependent Gr"uneisen parameters and mode dependent heat capacities. The density of Gr"uneisen parameters \mathrm\ensuremathΓ(\ensuremathν) as a function of frequency \ensuremathν, weighted by the number of phonon modes, is introduced and found to be illuminating in interpreting the TEC results. Using density functional perturbation theory and Gr"uneisen formalism for thermal expansion, we illustrate the general usefulness of this method by calculating the linear and volumetric TECs of a low-symmetry orthorhombic compound antimony sulfide (Sb2S3), which belongs to a large class of technologically and fundamentally important materials. Even though negative Gr"uneisen parameters are found for deformations in all three crystal directions, the \mathrm\ensuremathΓ(\ensuremathν) data rule out the occurrences of negative TECs at all temperatures. Sb2S3 exhibits a large thermal expansion anisotropy where the TEC in the b direction can reach as high as 13\ifmmode×\else\texttimes\fi10^\ensuremath-6 K^\ensuremath-1 at high temperatures, about two and seven times larger than the TECs in the c and a direction, respectively. Our work suggests a general and practical first-principles approach to calculate the thermal properties of other complicated low-symmetry systems.