Elasticity of agr-Cristobalite: A Silicon Dioxide with a Negative Poisson's Ratio.
Laser Brillouin spectroscopy was used to determine the adiabatic single-crystal elastic stiffness coefficients of silicon dioxide (SiO(2)) in the alpha-cristobalite structure. This SiO(2) polymorph, unlike other silicas and silicates, exhibits a negative Poisson's ratio; alpha-cristobalite contracts laterally when compressed and expands laterally when stretched. Tensorial analysis of the elastic coefficients shows that Poisson's ratio reaches a maximum value of -0.5 in some directions, whereas averaged values for the single-phased aggregate yield a Poisson's ratio of -0.16.
Yeganeh-Haeri
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A
Weidner
D J
DJ
Parise
J B
JB