Enhanced Superconductivity in X₄H₁₅ Compounds via Hole-Doping at Ambient Pressure

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Superconductivity in hydride materials is a key area of research for achieving high transition temperatures.
• Understanding the relationship between electronic structure and superconducting properties is crucial for material design.

Purpose of the Study:

• To computationally investigate X4H15 compounds for superconductivity under ambient or high-pressure conditions.
• To explore the impact of electronic structure engineering, specifically hole doping, on superconducting properties.
• To identify potential pathways for synthesizing high-temperature superconducting hydrides.

Main Methods:

• Density functional theory (DFT) calculations were employed for systematic investigation.
• Electron-phonon coupling analysis was performed to understand the mechanisms of superconductivity.
• Electronic structure and phonon modes were analyzed for various doping concentrations.

Main Results:

• Electron-doped X4H15 compounds (X4+) exhibit low transition temperatures (1-9 K).
• Hole-doped X4H15 compounds (X3+) demonstrate significantly enhanced superconductivity, reaching ~50 K at ambient pressure.
• Superconductivity in hole-doped systems arises from strong electron coupling with cation and hydrogen phonon modes.
• Pristine X3+4H15 compounds are unstable, but controlled hole doping of YZr3H15 is proposed as a viable synthesis route.

Conclusions:

• Strategic electronic structure modulation via hole doping is effective in optimizing superconducting properties in hydride systems.
• Hole-doped X4H15 compounds represent a promising class of materials for achieving high-temperature conventional superconductivity.
• The proposed synthesis route offers a practical approach toward ambient-pressure superconductors.