Martensitic fcc-to-hcp transformations in solid xenon under pressure: a first-principles study

Area of Science:

• Condensed matter physics
• Materials science
• Computational chemistry

Background:

• Solid xenon exhibits complex phase behavior under high pressure.
• Understanding pressure-induced transformations is crucial for materials science.

Purpose of the Study:

• To elucidate the mechanisms of the pressure-induced fcc-to-hcp phase transition in solid xenon.
• To investigate the role of energetics and kinetics in governing the transformation pathways.

Main Methods:

• First-principles calculations were employed to simulate the phase transition.
• Analysis of structural stability, enthalpy, and energy barriers was performed.

Main Results:

• Two distinct transformation pathways (path I and path II) were identified between 5 and 70 GPa.
• Path I involves sluggish stacking-disorder growth at lower pressures, while path II involves orthorhombic distortion at higher pressures.
• The transition switchover is influenced by both system enthalpy and kinetic energy barriers.

Conclusions:

• The pressure-induced fcc-to-hcp transformation in xenon is a complex process involving two distinct martensitic transformation types.
• A transition from twinned martensitic to slipped martensitic mechanisms occurs with increasing pressure.