Twisting-Induced Phonon Localization and Ultralow Thermal Conductivity in Penta-PdTe₂ Bilayer Revealed by a Universal...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• The development of novel 2D materials with unique properties is a key area of research.
• Pentagonal topologies are emerging as promising structures for new 2D materials.
• Penta-PdTe2 represents the heaviest elemental composition among synthesized 2D pentagonal materials, making its thermal properties of significant interest.

Purpose of the Study:

• To investigate the phonon transport behavior and lattice thermal conductivity of penta-PdTe2.
• To understand how interlayer stacking and twisting affect the thermal properties of penta-PdTe2.
• To explore the potential of pentagonal topology and elemental composition in tuning thermal conductivity in 2D materials.

Main Methods:

• Fine-tuning of the universal machine-learning potential, NEP89, using first-principles data for penta-PdTe2.
• Homogeneous non-equilibrium molecular dynamics simulations with the refined machine-learning potential.
• Application of Wigner transport theory to analyze phonon transport.

Main Results:

• Achieved an energy prediction error within 2.3 meV atom-1 for the machine-learning potential.
• Interlayer stacking reduced bilayer penta-PdTe2 thermal conductivity to 28.00% of the monolayer value.
• Interlayer twisting further reduced thermal conductivity, resulting in an ultralow value of (0.30 ± 0.059) W m-1 K-1.

Conclusions:

• The interplay between pentagonal topology, elemental composition, and twist engineering is an effective strategy for tuning phonon transport in 2D materials.
• Penta-PdTe2 exhibits ultralow thermal conductivity, suggesting potential applications in thermal management.
• This study provides a pathway for designing 2D materials with tailored thermal properties.