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Atomic Layer Deposition of Vanadium Dioxide and a Temperature-dependent Optical Model
Published on: May 23, 2018
Structural phase transition of vanadium at 69 GPa
Yang Ding1, Rajeev Ahuja, Jinfu Shu
1HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, Building 434E, 9700 South Cass Avenue, Argonne, IL 60439, USA. yding@hpcat.aps.anl.gov
Physical Review Letters
|March 16, 2007
Summary
Researchers observed a novel phase transition in vanadium at high pressures. This unique rhombohedral distortion occurs without volume change, differing from typical electronic transitions in elements.
Area of Science:
- Condensed Matter Physics
- Materials Science
- High-Pressure Physics
Background:
- Vanadium exhibits a body-centered-cubic structure under ambient conditions.
- Understanding phase transitions in elements under extreme conditions is crucial for materials science.
- Previous studies on elemental phase transitions often involve volume discontinuities.
Purpose of the Study:
- To investigate the phase behavior of vanadium at high pressures and room temperature.
- To characterize the nature of the observed phase transition.
- To elucidate the underlying mechanism driving this novel transition.
Main Methods:
- Synchrotron X-ray diffraction was employed to probe the structural changes in vanadium.
- High-pressure experiments were conducted in the range of 63-69 GPa.
- Analysis of pressure-volume data was performed to identify discontinuities.
Main Results:
- A phase transition was identified in vanadium at 63-69 GPa and room temperature.
- The transition involves a rhombohedral lattice distortion of the body-centered-cubic phase.
- No discontinuity in the pressure-volume data was observed during the transition.
Conclusions:
- The observed phase transition in vanadium is a novel phenomenon, distinct from conventional electronic transitions.
- The transition is likely driven by the softening of the C44 elastic tensor.
- Potential mechanisms include Fermi surface nesting, band Jahn-Teller distortion, and electronic topological transitions.
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