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Negative thermal expansion in CuCl: An extended x-ray absorption fine structure study
| Content Provider | Semantic Scholar |
|---|---|
| Author | Vaccari, Mattia Grisenti, Robert E. Fornasini, P. Rocca, Francesco Sanson, Andrea |
| Copyright Year | 2007 |
| Abstract | Extended x-ray absorption fine structure (EXAFS) has been measured from liquid helium to ambient temperature at the $\mathrm{Cu}\phantom{\rule{0.2em}{0ex}}K$ edge of copper chloride (CuCl) to investigate the local origin of negative thermal expansion. A quantitative analysis of the first coordination shell, performed by the cumulant method, reveals that the nearest-neighbor Cu-Cl interatomic distance undergoes a strong positive expansion, contrasting with the much weaker negative expansion of the crystallographic distance between average atomic positions below $100\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The anisotropy of relative thermal vibrations, monitored by the ratio $\ensuremath{\gamma}$ between perpendicular and parallel mean square relative displacements, is considerably high, while the diffraction thermal factors are isotropic. The relative perpendicular vibrations measured by EXAFS are related to the tension mechanism and to the transverse acoustic modes, which are considered responsible for negative thermal expansion in zinc-blende structures. |
| Starting Page | 184307 |
| Ending Page | 184307 |
| Page Count | 1 |
| File Format | PDF HTM / HTML |
| DOI | 10.1103/PhysRevB.75.184307 |
| Volume Number | 75 |
| Alternate Webpage(s) | http://alpha.science.unitn.it/~rx/raggi_x/rx_pdf_articoli/89_07_PRB_CuCl.pdf |
| Alternate Webpage(s) | https://doi.org/10.1103/PhysRevB.75.184307 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
