A systematic study on the phase diagram and superconductivity of ternary clathrate Ca-Sc-H at high pressures

• Published in: Physical chemistry chemical physics : PCCP Vol. 26; no. 4; pp. 3408 - 3414
• Main Authors: Yuan, Wenjie, Yang, Xu, Li, Shichang, Feng, Chunbao, Chen, Bole, Chang, Ying, Li, Dengfeng
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 24.01.2024
• Subjects: Clathrates; Convexity; Crystal structure; First principles; High pressure; High temperature superconductors; Hydrogen; Particle swarm optimization; Phase diagrams; Pressure dependence; Superconductivity
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/d3cp05086f

This work explores potential high-temperature superconductor materials in hydrogen-rich systems. Here, the crystal structure stabilities of ternary Ca-Sc-H systems under high-pressure ( = 100-250 GPa) and their superconductivities are investigated using the particle swarm optimization methodology combined with first-principles calculations. For the predicted candidate structures of Ca-Sc-H systems, the pressure-dependent phase diagram and thermodynamic convex hull were investigated across a wide range of compositions; the electronic properties of all the predicted phases were analyzed in detail to study the bonding behavior of these stable phases. We identified the crystal structures of four thermodynamically stable compounds: 3̄ -CaScH , -CaSc H , 2/ -Ca ScH , and 3̄ -CaScH . Among them, 3̄ -CaScH was predicted to have the highest value ( , 173 K) at 200 GPa. The discovery of this previously unreported pressure-induced decomposition of Ca-Sc-H systems will pave the way for investigations on the nature of hydrogen-metal interactions.