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High Pressure Polymorphism in Cesium
Science (New York, N.Y.)
|December 4, 1964
Summary
Researchers discovered a new cesium polymorph at high pressures. This face-centered-cubic structure exists between 42.2-42.7 kilobars, offering new insights into cesium
Area of Science:
- Solid-state physics
- Materials science
- Crystallography
Background:
- Cesium (Cs) exhibits complex phase transitions under high pressure.
- Previous studies have identified various cesium polymorphs, but high-pressure phases remain an active area of research.
Purpose of the Study:
- To identify and characterize new polymorphs of cesium under high pressure.
- To refine understanding of the pressure-dependent phase diagram of cesium.
Main Methods:
- High-pressure X-ray diffraction (XRD) measurements.
- Electrical resistance measurements as a function of pressure.
Main Results:
- Discovery of a new cesium polymorph (Cesium-V) stable between 42.2 and 42.7 kilobars at room temperature.
- The new polymorph possesses a face-centered-cubic (fcc) crystal structure with a lattice parameter a = 5.800 ± 0.007 Å at 42.5 kb.
- Cesium-II (also fcc) was observed to exist from 23.7 to 42.2 kb, with a lattice parameter a = 5.984 ± 0.011 Å at 41 kb.
Conclusions:
- The high-pressure behavior of cesium is more complex than previously understood.
- The newly discovered polymorph expands the known phase diagram of cesium.
- Improved resistance-pressure data and compressibility measurements provide valuable benchmarks for future studies.
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