Reversible devitrification in amorphous As2Se3 under pressure

Article

关键词: SHARP DIFFRACTION PEAK;    AUGMENTED-WAVE METHOD;    TO-METAL TRANSITION;    MEMORY-GLASS;    SEMICONDUCTORS;    AMORPHIZATION;    SIMULATION;    SCATTERING;    PHASES;    QUARTZ;   

DOI  :  10.1103/PhysRevB.94.195211

来源: SCIE

【 摘 要 】

In pressure-induced reversible structural transitions, the term reversible refers to the recovery of the virgin structure in a material upon complete decompression. Pressure-induced amorphous-to-crystalline transitions have been claimed to be reversible, but evidence that amorphous material recovers its virgin amorphous structure upon complete depressurization has been lacking. In amorphous As2Se3 (a-As2Se3) chalcogenide, however, we report a novel reversible amorphous-to-crystalline transition that provides compelling experimental evidence that upon complete decompression, the recovered amorphous phase is structurally the same as that of the virgin (as-cast) amorphous phase. Combining the experimental results with ab initio molecular dynamics simulations, we elucidate that the amorphization ismediated by a surplus of total free energy in the high-pressure face-centered cubic phase as compared to the virgin amorphous phase and that the structural recovery to the virgin amorphous phase is a consequence of an enhancement in covalent bonding character over interlayer forces upon complete decompression. Furthermore, we observed a two-dimensional to three-dimensional network transition under compression and its reversibility upon decompression.

【 授权许可】

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