Pressure Stabilized Lithium-Aluminum Compounds with Both Superconducting and Superionic Behaviors

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Chemistry

Background:

• Superconductivity (electron dynamics) and superionic behavior (ion dynamics) are crucial phenomena with significant application potential.
• Investigating systems exhibiting both properties is key to understanding complex material behaviors.
• High pressure conditions can stabilize exotic material phases.

Purpose of the Study:

• To explore the possibility of coexisting superconductivity and superionic behavior in the same material system.
• To identify stable lithium-aluminum (Li-Al) compounds under high pressure.
• To investigate the dynamic properties of electrons and ions in these compounds.

Main Methods:

• Crystal structure prediction algorithms.
• First-principle calculations.
• Machine learning techniques.
• Analysis of electronic density of states and diffusion mechanisms.

Main Results:

• Identification of stable Li-Al compounds exhibiting electride behavior under high pressure.
• Observation of two-dimensional electron gas characteristics in the electronic density of states.
• Estimation of a superconducting transition temperature of ~29 K for Li6Al at 150 GPa.
• Prediction of a superionic state in Li6Al across a wide temperature and pressure range.
• Electride influence on diffusion attributed to atomic collective motion in Li6Al.

Conclusions:

• Li-Al compounds under high pressure can host both superconducting and superionic properties.
• The electride nature and 2D electron gas characteristics are linked to these phenomena.
• Alkali metal alloys are promising platforms for studying pressure- and temperature-dependent material properties.