Details

Autor(en) / Beteiligte

• Kimizuka, H
• Kaburaki, H
• Kogure, Y

Titel

Mechanism for negative poisson ratios over the alpha- beta transition of cristobalite, SiO2: A molecular-dynamics study

Ist Teil von

• Physical review letters, 2000-06, Vol.84 (24), p.5548-5551

Ort / Verlag

United States

Erscheinungsjahr

2000

Quelle

American Physical Society

Beschreibungen/Notizen

• The adiabatic elastic constants ( C(ij)) of cristobalite have been evaluated successfully over the temperature range of 300-1800 K using the molecular-dynamics method with a fluctuation formula. Cristobalite shows a negative Poisson ratio over this temperature range. However, the mechanisms differ between the alpha and beta phases. In the cubic beta phase, C44 exhibits a value extremely close to C11 rather than C12, in contrast to the Cauchy relation. This predicts a remarkable property that the longitudinal and transverse velocities coincide for the acoustic waves propagating along the [100] direction.