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Large structural modulations in incommensurate Te-III and Se-IV
1School of Physics and Centre for Science at Extreme Conditions, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, United Kingdom.
Physical Review Letters
|December 20, 2003
Summary
High-pressure tellurium (Te-III) exhibits a novel incommensurate monoclinic structure, stable over a wide pressure range. This study reveals a previously unknown structural phase and its pressure-dependent behavior.
Area of Science:
- Solid State Physics
- Materials Science
- Crystallography
Background:
- Understanding the high-pressure behavior of elements is crucial for materials science.
- Previous studies suggested a distinct Te-IV phase in tellurium at 10.6 GPa.
Purpose of the Study:
- To investigate the high-pressure crystal structure of tellurium.
- To characterize the phase transitions and structural properties of tellurium under pressure.
Main Methods:
- High-pressure X-ray diffraction was employed to study tellurium.
- Analysis of diffraction data revealed the incommensurate monoclinic structure.
Main Results:
- Tellurium (Te-III) was found to possess an incommensurate monoclinic structure (superspace group I(')2/m(0q0)s0).
- This structure is stable from 4.5(2) to 29.2(7) GPa, contradicting previous reports of a Te-IV phase.
- The incommensurate wave vector shows strong, nonlinear pressure dependence.
- Selenium-IV (Se-IV) was identified as isostructural with Te-III.
Conclusions:
- The high-pressure phase of tellurium exhibits a novel incommensurate structure.
- The pressure-induced phase transitions in tellurium are more complex than previously understood.
- The discovery of isostructural behavior between tellurium and selenium under pressure offers new avenues for research.