Papers
Topics
Authors
Recent
Gemini 2.5 Flash
Gemini 2.5 Flash
173 tokens/sec
GPT-4o
7 tokens/sec
Gemini 2.5 Pro Pro
46 tokens/sec
o3 Pro
4 tokens/sec
GPT-4.1 Pro
38 tokens/sec
DeepSeek R1 via Azure Pro
28 tokens/sec
2000 character limit reached

X-ray driven first-order phase transition in GeO2 glass under pressure (1705.02463v1)

Published 6 May 2017 in cond-mat.mtrl-sci

Abstract: Unprecedented bright and intense synchrotron X-rays have been widely used to unravel numerous compelling electronic and structural properties using a large variety of physical techniques, while the puzzling phenomenon is the uncertainties of measurements due to X-ray induced considerable electronic and structural changes of a matter under study. Here, we report an X-ray driven first-order tetrahedral-octahedral phase transition in GeO2 glass at high pressure using X-ray absorption fine structure (XAFS) with a nano-polycrystalline diamond anvil (NPD) cell. Upon X-ray irradiation from an undulator device, the XAFS spectrum at 5.4 GPa, which is below the threshold pressure of tetrahedral to pentahedral transition, starts to progressively approach the spectrum of octahedral GeO2 at 20.4 GPa. Detailed analysis indicates that both the nearest distance and coordination number of GeO2 glass at 5.4 GPa increase to those of a fully octahedral glass above 20 GPa, while negligible changes were found at other low pressures. These observations demonstrate that X-ray irradiation can be served as an alternative stimulus for forming dense matter under pressure, as the well-known external stimuli of pressure and temperature. Dense matter formed under external stimuli is crucial for understanding the formation, differentiation and evolution of planet and Earth. Attention for the X-ray induced structural uncertainties is called, especially for addressing metastable states under extreme conditions which may become undetectable in terms of intense synchrotron X-rays as structural tools.

Summary

We haven't generated a summary for this paper yet.