Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Materials Science

Background:

• Indium nitride (InN) is a semiconductor with potential applications in electronics and optoelectronics.
• Understanding the behavior of InN under high pressure is crucial for its technological applications and fundamental physics.
• Previous studies have explored InN properties, but high-pressure phase transitions and the role of phonons require further investigation.

Purpose of the Study:

• To investigate the structural, electronic, and vibrational properties of InN under high pressure.
• To determine the pressure-induced phase transition and its associated electronic band gap changes.
• To elucidate the role of phonons in the phase transition mechanism of InN.

Main Methods:

• Utilized the pseudo-potential plane wave (PP-PW) method within the generalized-gradient approximation (GGA) of density functional theory (DFT).
• Employed the linear response approach and density functional perturbation theory (DFPT) to calculate phonon frequencies and densities of states (DOS).
• Applied the harmonic approximation method to describe phonon properties.

Main Results:

• Identified a structural phase transition from the wurtzite (B4) to the rocksalt (B1) phase at approximately 12.7 GPa.
• Observed a transition of the electronic band gap from direct to indirect at the phase transition pressure.
• Demonstrated that phonon properties significantly influence the phase transition mechanism and the instability of the wurtzite phase prior to transition.

Conclusions:

• High pressure induces a significant structural and electronic transformation in InN.
• Phonon dynamics are intrinsically linked to the high-pressure phase transition in InN.
• The computational results align well with existing experimental data at zero pressure.