Shear melting of silicon and diamond and the disappearance of the polyamorphic transition under shear
| Autor: | Thomas Reichenbach, Michael Moseler, Andreas Klemenz, Hiroshi Uetsuka, Lars Pastewka, Adrien Gola, Gianpietro Moras |
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| Přispěvatelé: | Publica |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) Silicon molecular dynamic chemistry.chemical_element Diamond silicon shear-induced amorphization 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology 01 natural sciences chemistry Shear (geology) diamond 0103 physical sciences engineering General Materials Science Composite material 010306 general physics 0210 nano-technology |
| Popis: | Molecular dynamics simulations of diamond-cubic silicon and carbon under combined shear and compression show the formation of an amorphous solid with liquidlike structure at room temperature. Consistent with the opposite density changes of the two crystals upon melting, the amorphous material is denser than the crystal in silicon and less dense than the crystal in carbon. As a result, its rate of formation is enhanced by pressure in silicon but suppressed in carbon. These results are particularly unexpected for silicon, whose amorphous structure is supposed to be liquidlike only when hydrostatically compressed above the polyamorphic transition pressure (∼14GPa). Below this pressure, amorphous silicon is expected to have a low-density structure with density close to that of the diamond-cubic crystal. Our simulations show that this polyamorphic transition disappears under shear and high-density, liquidlike amorphous silicon with metallic ductility forms even at low pressure. These results are potentially transferable to other diamond-cubic crystals, like germanium and ice Ih, and provide insights into nonequilibrium materials transformations that govern friction and wear in tribological systems. |
| Databáze: | OpenAIRE |
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