A semiconductive superhard FeB₄ phase from first-principles calculations

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• The synthesis of the oP10-FeB4 phase was recently achieved.
• Theoretical predictions guide experimental synthesis of novel materials.

Purpose of the Study:

• To propose a new high-pressure phase of iron tetraboride (FeB4) using first-principles calculations.
• To investigate the structural and electronic properties of this predicted phase.

Main Methods:

• First-principles calculations were employed.
• Thermodynamic stability was assessed via enthalpy calculations as a function of pressure.
• Phonon dispersion was analyzed to understand phase transitions.

Main Results:

• A novel tetragonal phase (tP10-FeB4) with space group P42/nmc was identified.
• This phase is predicted to be stable above approximately 65.9 GPa, potentially forming from the oP10-FeB4 phase.
• Boron atoms form tetrahedron configurations within the tP10-FeB4 structure.
• Softening of acoustic phonons at T points suggests a driving force for the phase transition.

Conclusions:

• The tP10-FeB4 phase is a probable high-pressure outcome.
• This phase exhibits potential as a superhard semiconductor material.