Ab initio simulation of permanent densification in silica glass

作者：Ryuo Emina^*; Wakabayashi Daisuke; Koura Akihide; Shimojo Fuyuki

来源：Physical Review B, 2017, 96(5): 054206.

DOI：10.1103/PhysRevB.96.054206

To clarify the microscopic structure of densified SiO2 glass, we have conducted ab initio molecular-dynamics simulations on the decompression process of SiO2 glass in its relaxed state from high pressures up to 40 GPa. When decompressed from high pressures above at least 15 GPa, the density and structure always converge to those of densified glass, while the coordination number of silicon decreases to four rapidly. This is in good agreement with previous experimental studies and strongly suggests that densified glass behaves as a high-pressure polymorph of SiO2 glass. In comparison to ordinary glass, although the coordination number of densified glass is almost the same, the size of an intermediate-range network consisting of SiO4 tetrahedra is smaller. Detailed analyses clarify that SiO4 tetrahedra in densified glass are deformed and the Si-O bonds are less covalent.

• 出版日期2017-8-16