Phase stability limits via non-equilibrium normal mode analysis
| Autor: | Brian J. Reardon, John Kieffer |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Philosophical Magazine B. 77:907-924 |
| ISSN: | 1463-6417 1364-2812 |
| DOI: | 10.1080/13642819808214842 |
| Popis: | Alkali chlorides in both their rock-salt and CsCl modifications were isotropically expanded or compressed to produce non-equilibrium structures while preserving the crystal symmetries and perfect force balance. These structures were analysed by determining the eigenvalues of the linearized Hamiltonian equations of motion. This procedure, which is similar to normal mode analysis, yields all elastic coefficients and the spectrum of rates of motion, which can include oscillatory as well as aperiodic modes. In balanced structures, the onset of aperiodic modes of motion coincides with singularities or roots in the density dependence of elastic coefficients. This onset is interpreted as the limit of stability for a given crystallographic phase and, by comparing the values of the various elastic constants, some information about the type of transition that is impending at those densities can be obtained. Results for chlorides with varying alkali cation are consistent with the experimentally observed pha... |
| Databáze: | OpenAIRE |
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