Tunable Phonon Scattering and Phonon Coherence in Bilayer Penta-PdPSe

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Materials Science

Background:

• Stacking engineering is crucial for tuning thermal transport in layered materials by modifying interlayer phonon dynamics.
• The recent experimental synthesis of puckered pentagonal penta-PdPSe provides a new platform for studying stacking effects.

Purpose of the Study:

• To systematically investigate the impact of stacking configurations (AA and AA-mirror) on the thermal transport properties of bilayer penta-PdPSe.
• To understand the interplay between electronic structure, phonon dynamics, and thermal conductivity in different stacking arrangements.

Main Methods:

• First-principles calculations were employed to determine electronic structures and phonon properties.
• The unified theory of thermal transport was utilized to calculate lattice thermal conductivities.
• Analysis focused on phonon group velocities, anharmonic scattering, and phonon coherence contributions.

Main Results:

• Both AA and AA-mirror stacking exhibit semiconducting behavior with indirect band gaps around 0.91-0.94 eV.
• Lattice thermal conductivities differ significantly between stacking structures, with AA-mirror showing higher values (1.22-1.29 W m⁻¹ K⁻¹) compared to AA (0.97-1.13 W m⁻¹ K⁻¹).
• AA-mirror stacking enhances particle-like phonon transport due to stronger interlayer coupling, while AA stacking shows a more balanced contribution from particle-like transport and phonon coherence.

Conclusions:

• Interlayer stacking order is a powerful strategy for engineering phonon transport and thermal conductivity in 2D pentagonal materials like penta-PdPSe.
• The findings highlight the potential for designing materials with tailored thermal properties through controlled stacking.
• Understanding stacking-dependent phonon dynamics is key to optimizing thermal management in advanced electronic devices.