Phase behavior and atomic dynamics in RbNa_1-: insights from machine learning interatomic potentials based onab...

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Materials Science

Background:

• Liquid alkali metal alloys are vital for advanced applications like coolants and batteries.
• Limited understanding of their complex phase behavior hinders safe and effective utilization.
• Environmental conservation and technological progress drive research in these systems.

Purpose of the Study:

• To comprehensively investigate factors determining the phase diagram of RbNa1-x liquid alloys.
• To understand the interplay of thermodynamic and structural properties influencing phase stability.
• To elucidate the dynamic behavior and atomic interactions within these alloys.

Main Methods:

• Employed thermodynamic integration and machine learning interatomic potentials.
• Utilized *ab initio* molecular dynamics simulations to reproduce experimental results.
• Analyzed energy, entropy, volume, atomic mass, coordination numbers, and diffusion dynamics.

Main Results:

• Uncovered the critical balance between energy and entropy contributions to phase stability.
• Identified volume and atomic mass as significant factors in the liquid phase.
• Observed distinct atomic clustering: Na atoms avoided proximity, Rb atoms clustered.
• Revealed asymmetric diffusion dynamics: Rb diffusion increased with concentration, Na diffusion decreased.

Conclusions:

• Provides significant insights into the phase stability of RbNa1-x liquid alloys.
• Highlights the importance of understanding structural and dynamic properties for alloy design.
• Findings contribute to the safe and efficient application of liquid metal alloys in energy technologies.