Anomalous mode, elastic constants and phonon images in CaWO4

Martensitic Transformation and Elastic Constants

Elastic constants of natural quartz.

The elastic constants of a natural-quartz sphere using resonance-ultrasound spectroscopy (RUS) are measured. The measurements of the near-traction-free vibrational frequencies of the sphere are matched with the predicted frequencies from the dynamic theory of elasticity, with optimized estimates for the elastic constants driving the differences between these sets of frequencies to a minimal val...

Quantum manifestation of elastic constants in nanofilms.

Generally, there are two distinct effects in modifying the properties of low-dimensional nanostructures: surface effect (SE) due to increased surface-volume ratio and quantum size effect (QSE) due to quantum confinement in reduced dimension. The SE has been widely shown to affect the elastic constants and mechanical properties of nanostructures. Here, we demonstrate that QSE can also have a str...

Second Order Elastic Constants, Third Order Elastic Constants, Pressure Derivatives of Second Order Elastic Constants and the Low Temperature Thermal Expansion of D-tin

The complex behaviour of metals under severe thermal and stress environments is influenced markedly by their elastic properties. Indeed the response of a material tc~ an applied stress is always determined by the elastic constants and their pressure derivatives. Furthermore, both the mechanical and thermodynamic equation;$ of state of a metal that contains dislocations require detailed knowledg...

Phonon and elastic instabilities in MoC and MoN

We present several results related to the instability of MoC and MoN in the B1 ~sodium chloride! structure. These compounds were proposed as potential superconductors with moderately high transition temperatures. We show that the elastic instability in B1-structure MoN, demonstrated several years ago, persists at elevated pressures, thus offering little hope of stabilizing this material without...