Superconducting Lithium Hydride in a Chemical Capacitor Setup: A Theoretical Study

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Lithium hydride (LiH) is an ionic material that has resisted experimental metallization.
• Achieving metallization typically requires extreme pressures, limiting practical applications.

Purpose of the Study:

• To demonstrate the metallization of LiH under ambient pressure conditions.
• To investigate the stability and electronic properties of doped LiH.
• To explore the potential for superconductivity in metallized LiH.

Main Methods:

• A novel "chemical capacitor" setup was employed to facilitate LiH metallization.
• Density Functional Theory (DFT) calculations were used to model the doped LiH systems.
• Electron-phonon coupling strength and superconducting critical temperature were computationally predicted.

Main Results:

• A single layer of LiH withstood doping up to 0.61 holes per H atom without structural collapse in a ZrC | LiH | ZrC system.
• Electron-phonon coupling strength (λ) reached 2.1 in a TiO | LiH | TiO system, indicating strong coupling.
• Superconductivity calculations predicted a maximum critical temperature (Tc) of 17.5 K for 0.31-hole-doped LiH with (LiBaF3)2 support layers.

Conclusions:

• The chemical capacitor approach successfully enables LiH metallization at ambient pressure.
• Doped LiH exhibits remarkable stability and strong electron-phonon coupling.
• Metallized LiH presents a promising candidate for high-temperature superconductivity without external pressure.