Stability and superconductivity of hexagonal prism-structured polyhydrides X2MgH18 (X = Li, Na, K, Rb, Cs) under
Liliang Zha1, Jiajun Jiang1, Yamin Xue1
1Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China. plpeng@shiep.edu.cn.
Physical Chemistry Chemical Physics : PCCP
|February 3, 2025
Summary
Researchers explored new hydride superconductors, discovering Li2MgH18 and Na2MgH18 exhibit stable superconductivity at moderate pressures. Hydrogen atom vibrations are key to their high transition temperatures.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Computational Chemistry
Background:
- Ultra-high pressures currently limit hydride superconductor development.
- Discovering stable, high-temperature superconductors at moderate pressures is crucial for practical applications.
Purpose of the Study:
- To search for novel stable hydride superconductors within the X2MgH18 (X = Li, Na, K, Rb, Cs) chemical formula.
- To investigate the stability and superconducting properties of identified structures under pressure.
Main Methods:
- Extensive computational search for various X2MgH18 structures.
- Analysis of structural stability using dynamic stability calculations.
- Investigation of superconducting properties via theoretical calculations.
Main Results:
- Identified a hexagonal prism structure (space group C2/m) for X2MgH18.
- Li2MgH18 and Na2MgH18 exhibit dynamic stability and superconductivity at moderate pressures (20-235 GPa).
- Achieved superconducting transition temperatures up to ~147 K for Na2MgH18.
Conclusions:
- Hydrogen atom vibrations are the primary drivers of superconductivity in these hydrides.
- Structural distortions influence H-H covalent and metallic bonds, enhancing superconducting transition temperatures.
- This research offers new avenues for exploring moderate-pressure hydride superconductors.
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