Accessing slow diffusion in solids by employing metadynamics simulation

Area of Science:

• Materials Science
• Computational Chemistry
• Solid-State Physics

Background:

• Molecular dynamics (MD) simulations are vital for studying atomic and molecular transport in condensed matter.
• Standard MD struggles with systems exhibiting slow atomic diffusion, limiting investigations on feasible timescales.

Purpose of the Study:

• To demonstrate the efficacy of metadynamics (MTD) for accessing slow atomic transport mechanisms in solids.
• To investigate the microscopic mechanisms of Na+ diffusion in NASICON solid solutions (NaZr2(PO4)3 and Na4Zr2(SiO4)3).

Main Methods:

• Utilized metadynamics (MTD), an advanced simulation technique, to overcome timescale limitations in atomistic simulations.
• Performed calculations on NaZr2(PO4)3 and Na4Zr2(SiO4)3, key NASICON materials.
• Compared MTD results with climbing image nudged elastic band (CI-NEB) calculations and experimental data.

Main Results:

• Successfully accessed and analyzed the microscopic mechanism of slow Na+ diffusion in NASICON materials.
• Provided new insights into correlated ion hopping events and their impact on the effective diffusion barrier.
• Achieved results within reasonable computational timeframes, overcoming standard MD limitations.

Conclusions:

• Metadynamics (MTD) is a powerful and efficient technique for studying slow atomic diffusion in solids.
• The study elucidates Na+ transport mechanisms in NASICON, offering valuable data for materials development.
• The findings validate MTD's capability to complement traditional methods like CI-NEB and experimental observations.