Effective Modulus of Elasticity and Grüneisen Parameter of Chalcogenide Glasses in the As–Tl–S System

Elastic Moduli: a Tool for Understanding Chemical Bonding and Thermal Transport in Thermoelectric Materials

“…[3,[178][179][180] Equation (10) was initially derived within the Debye model for a cubic system but has been shown to provide reasonable results for other symmetries as well. [3] g ¼ 3 2…”

“…Since experimental and computed room temperature elastic moduli are more widely available than temperature‐dependent data, an expression relating γ to the Poisson's ratio, μ , has recently gained popularity [3,178‐180] . Equation 10 was initially derived within the Debye model for a cubic system but has been shown to provide reasonable results for other symmetries as well [3] $$$\vcenter{\openup.5em\halign{$\displaystyle{#}$\cr \gamma = {3 \over 2}{B \over {\rho {\bar v}^2 }}\hfill\cr}}$$$ …”

“…Nevertheless, the room temperature k L of the Hg compound is around three times lower than that of the Zn-containing one. By combining the measured k L and v sound , an estimate of τ as a function of temperature was extracted using Equation (3). A drastic decrease in τ for the Hg-containing sample was found and hypothesized to be connected with a change in point defect scattering.…”

“…This leads to marked disparities in transport properties—in particular phonon transport. Acoustic phonon velocities are determined directly from the elastic moduli, while the Grüneisen parameter, which determines phonon‐phonon scattering rates, can be estimated from the temperature‐dependence of the elastic moduli [2] or from the Poisson's ratio [3] . Elastic moduli also play a role in electronic transport by influencing electron‐phonon scattering (i.e., acoustic deformation potential scattering) [4, 5] .…”

“…Acoustic phonon velocities are determined directly from the elastic moduli, while the Grüneisen parameter, which determines phonon-phonon scattering rates, can be estimated from the temperaturedependence of the elastic moduli [2] or from the Poisson's ratio. [3] Elastic moduli also play a role in electronic transport by influencing electron-phonon scattering (i.e., acoustic deformation potential scattering). [4,5] Further, because elastic moduli are second-order derivatives of the Gibb's free energy, temperature-dependent measurements serve as a powerful tool in the investigation and detection of both firstand second-order phase transitions.…”