Related papers: Interplay between phonons and anisotropic elastici…
The thermal properties of materials are critically important to various technologies and are increasingly the target of materials design efforts. However, it is only relatively recent advances in first-principles computational techniques…
We use a symmetry-motivated approach to analyse neutron pair distribution function data to investigate the mechanism of negative thermal expansion (NTE) in ReO$_3$. This analysis shows that the local structure of ReO$_3$ is dominated by an…
A definition of the Gr\"uneisen parameters for anisotropic materials is derived based on the response of phonon frequencies to uniaxial stress perturbations. This Gr\"uneisen model relates the thermal expansion in a given direction…
Negative thermal expansion (NTE) describes the anomalous propensity of materials to shrink when heated. Since its discovery, the NTE effect has been found in a wide variety of materials with an array of magnetic, electronic and structural…
The rare physical property of negative thermal expansion (NTE) is intriguing because materials with large NTE over a wide temperature range can serve as high-performance thermal expansion compensators. However, applications of NTE are…
The negative thermal expansion (NTE) mechanism in Cu2O has been characterised via mapping of different Cu2O structural flexibility models onto phonons obtained using ab-initio lattice dynamics. Low frequency acoustic modes that are…
We have investigated the anisotropic thermal expansion of graphite using ab-initio calculation of lattice dynamics and anharmonicity of the phonons, which reveal that the negative thermal expansion (NTE) in the a-b plane below 600 K and…
We investigate the harmonic and anharmonic contributions to the phonon spectrum of lead telluride, and perform a complete characterization of how the anharmonic effects dominate the phonons in PbTe as temperature increases. This effect is…
Understanding electrical resistivity in metals remains a central challenge in quantifying charge transport at finite temperature. Current first-principles calculations based on the Boltzmann transport equation often match experiments, yet…
The anharmonic phonon properties of SnSe in the Pnma phase were investigated with a combination of experiments and first-principles simulations. Using inelastic neutron scattering (INS) and nuclear resonant inelastic X-ray scattering…
We have investigated temperature dependence of the lattice parameters and the unit cell volume of ZnF$_2$ by neutron diffraction and have discovered negative thermal expansion (NTE) at low temperature. To understand why this simple compound…
We have devised an isotropic interaction potential that gives rise to negative thermal expansion (NTE) behavior in equilibrium many-particle systems in both two and three dimensions over a wide temperature and pressure range (including zero…
Origin and composition dependence of the anisotropic thermomechanical properties are elucidated for Ba1-xSrxZn2Si2O7 (BZS) solid solutions. The high-temperature phase of BZS shows negative thermal expansion (NTE) along one crystallographic…
We use a combination of variable-temperature / variable-pressure neutron powder diffraction, variable-pressure inelastic neutron scattering, and quantum chemical calculations to interrogate the behaviour of the negative thermal expansion…
Negative thermal expansion in ZrW2O8 was investigated using a flexibility analysis of ab-initio phonons. It was shown that no previously proposed mechanism adequately describes the atomic-scale origin of negative thermal expansion in this…
We have investigated the finite temperature elastic properties of AlRE (RE=Y, Tb, Pr, Nd, Dy) with B2-type structures from first principles. The phonon free energy and thermal expansion is obtained from the quasiharmonic approach based on…
The discovery of unusual negative thermal expansion (NTE) provides the opportunity to control the common but much desired property of thermal expansion, which is valuable not only in scientific interests but also in practical applications.…
Thermal expansion is a problem in many technological applications and its control represents a challenge in materials design. In this Letter, after studying the correlation between thermal expansion, cubic-to-rhombohedral transition and…
Understanding the microscopic processes affecting the bulk thermal conductivity is crucial to develop more efficient thermoelectric materials. PbTe is currently one of the leading thermoelectric materials, largely thanks to its low thermal…
Negative thermal expansion (NTE) - the phenomenon where some materials shrink rather than expand when heated - is both intriguing and useful, but remains poorly understood. Current understanding hinges on the role of specific vibrational…