Soft Manifold Dynamics behind Negative Thermal Expansion
نویسندگان
چکیده
منابع مشابه
Soft manifold dynamics behind negative thermal expansion.
Minimal models are developed to examine the origin of large negative thermal expansion in underconstrained systems. The dynamics of these models reveals how underconstraint can organize a thermodynamically extensive manifold of low-energy modes which not only drives negative thermal expansion but extends across the Brillioun zone. Mixing of twist and translation in the eigenvectors of these mod...
متن کاملFrustrated soft modes and negative thermal expansion in ZrW2O8.
Negative thermal expansion (NTE) in cubic ZrW2O8 has generated much interest due to its large, isotropic, and temperature independent behavior. Here, x-ray absorption fine structure data are presented for various atom pairs, providing evidence that the low-energy modes causing NTE correspond to the correlated vibrations of a WO4 tetrahedron and its three nearest ZrO6 octahedra. This involves tr...
متن کاملNegative Thermal Expansion
Introduction Many materials which we encounter in everyday life expand on heating. This fact of life is easily highlighted with a simple experiment that we are all familiar with and involves a metallic sphere passing through a metal ring. At room temperature, the sphere is of such a size that it can easily pass through the ring, but after the sphere is heated, it will have expanded with the res...
متن کاملNegative Thermal Expansion in Ba0.5Sr0.5Zn2SiGeO7
Solid solutions with the composition Ba0.5Sr0.5Zn₂Si2-xGexO₇ and BaZn₂Si2-xGexO₇ were prepared with different values of x using a conventional mixed oxide route. Both compounds exhibit very different thermal expansion, which is due to the different crystal structures. Ba0.5Sr0.5Zn₂Si2-xGexO₇ solid solutions exhibit the structure of high-temperature BaZn₂Si₂O₇ and show negative thermal expansion...
متن کاملNegative thermal expansion in beta-quartz
M.T. Dove ()) Dept. of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK Abstract Computer modelling and theoretical analysis are used to explain the nearly zero and slightly negative coefficients of thermal expansion in b-quartz well above the a-b phase transition temperature. Quartz was selected for study as an archetypal material with a framework structure of sti...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Physical Review Letters
سال: 2008
ISSN: 0031-9007,1079-7114
DOI: 10.1103/physrevlett.101.015501