219 / 2023-04-15 22:55:00

Pressure-induced crystallization and metallization in amorphous As20Se80

高压物理与材料科学 > 相变与机制-海报

Chalcogenide glasses exhibit a wide range of physical properties such as infrared transparency, high refractive indices, and reversible amorphous-to-crystalline transitions and can be easily shaped into optical and memory storage devices. Among them, the arsenic selenide glasses As_xSe_1-x are considered a promising family because they are good candidates for optical switching, mid-infrared laser sources, and optical fibers.

Pressure is a controlled thermodynamic parameter that can tune the structure and properties of the materials. The study of amorphous materials under pressure has attracted great attention from physicists and materials scientists. Importantly, amorphous chalcogenides are of great importance because of the demonstration o amorphous-to-amorphous and amorphous-to-crystalline transitions under pressure, as they undergo compression because of their relatively open structure at ambient conditions. However, amorphous As₂₀Se₈₀ (a-As₂₀Se₈₀), which is a good glass former and important material for its technological use in infrared optics, has not yet been explored under pressure.



In this work, we explore the vibrational and structural properties of a-As₂₀Se₈₀ under pressure up to ~30 GPa using a diamond anvil cell. In-situ high-pressure synchrotron-based X-ray diffraction (XRD), Raman spectroscopy and four-probe resistivity measurements have been performed to explore its behavior under compression. The structural transition from amorphous to crystalline has been detected around 12 GPa, and the crystallization is fully completed around 22 GPa, as concluded by both Raman spectroscopy and XRD analysis. In Raman spectroscopy analysis we observe a mode softening which indicates lattice instability and atomic re-arrangements during the gradual crystallization under compression.