Related Experiment Videos
Structural phase transitions in heavy alkali metals under pressure.
Jorge M Osorio-Guillén1, Rajeev Ahuja, Börje Johansson
1Department of Physics, Uppsala University, Uppsala, BOX 530 751 21 (Sweden). jorge.osorio@fysik.uu.se
Summary
High-pressure studies reveal new complex crystal structures for cesium and rubidium, confirming experimental findings. The d-orbital occupation is key to these complex structures, clarifying phase transitions.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Computational Chemistry
Background:
- Cesium (Cs) and Rubidium (Rb) exhibit complex phase transitions under extreme pressure.
- Previous experimental data suggested new crystallographic phases for Cs and Rb at high pressures.
Purpose of the Study:
- To theoretically investigate the crystal structures of cesium and rubidium under high compression.
- To validate recent experimental observations of novel Cs and Rb phases.
- To elucidate the electronic structure driving these phase transitions.
Main Methods:
- Theoretical calculations of crystal structures.
- High-pressure computational simulations.
- Analysis of electronic orbital occupations, specifically d-orbital contributions.
Main Results:
- Confirmed new complex crystal structures for the Cs III and Rb III phases.
- Calculated transition pressures closely matched experimental measurements.
- Identified a d-orbital occupation number of approximately 0.52 as critical for complex structure formation.
Conclusions:
- The study validates the existence of new crystallographic phases in Cs and Rb under high pressure.
- The long-debated isostructural phase transition in cesium is reclassified as a new crystallographic phase transition.
- Electronic structure, particularly d-orbital filling, plays a pivotal role in determining high-pressure phases of alkali metals.