Quasi-Ab initio molecular dynamic study of Fe melting

Area of Science:

• Geophysics
• Materials Science
• Computational Physics

Background:

• The melting point of iron (Fe) at high pressures is crucial for understanding Earth's core dynamics.
• Existing experimental data on iron's melting curve at high pressures are controversially divided into 'low' and 'high' temperature regions.
• Resolving this discrepancy is vital for accurate geophysical models.

Purpose of the Study:

• To computationally investigate the melting behavior of hexagonal close-packed (hcp) iron under high pressure.
• To establish a reliable ab initio simulated melting curve for iron at extreme conditions.
• To compare simulation results with existing experimental data to resolve the high-pressure melting controversy.

Main Methods:

• Employed molecular dynamics (MD) simulations.
• Utilized the full potential linear muffin tin orbital (FP-LMTO) method for accurate electronic structure calculations.
• Calculated the iron melting curve from first principles (ab initio).

Main Results:

• The ab initio simulated iron melting curve aligns with low-temperature experimental data at lower pressures.
• Crucially, the simulated curve shows excellent agreement with high-temperature, shockwave-based experimental data at higher pressures.
• This provides strong support for the presented melting curve over existing controversial datasets.

Conclusions:

• The study presents a robust ab initio melting curve for hcp iron at high pressures.
• The findings support the high-temperature experimental data, resolving a long-standing controversy in the field.
• This refined understanding of iron's melting behavior has significant implications for geophysics and planetary science.