Peierls transition in sodium under high pressure: a first-principles study.
1State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, People's Republic of China.
Summary
First-principles calculations reveal sodium
Area of Science:
- Condensed matter physics
- Materials science
- Computational physics
Background:
- Recent experimental discovery of the oP8 phase of sodium.
- Previous theoretical predictions for sodium's high-pressure phases.
Purpose of the Study:
- Investigate the electronic structure of the novel oP8 sodium phase.
- Determine the phase transition pressures and mechanisms.
- Clarify the charge distribution and electronic properties of the oP8 structure.
Main Methods:
- First-principles calculations.
- Density Functional Theory (DFT).
- Analysis of electronic structure, charge density, and electronic density of states.
Main Results:
- The I-43d to oP8 phase transition in sodium occurs at approximately 155 GPa and 0 K.
- The oP8 structure exhibits a unique nonequilateral triangle Na(3) arrangement with charge accumulation in voids.
- A deeper pseudogap near the Fermi level is observed in the oP8 structure due to symmetry breaking.
- The Peierls mechanism, driven by Na(3) clusters forming a 1D charge density wave, governs the transition to the oP8 phase.
Conclusions:
- The study refines the understanding of sodium's high-pressure phase diagram, correcting previous predictions.
- The oP8 phase possesses distinct electronic and structural characteristics driven by the Peierls mechanism.
- This work provides crucial insights into the behavior of alkali metals under extreme pressure conditions.
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