Twisting‐Induced Phonon Localization and Ultralow Thermal Conductivity in Penta‐PdTe ₂ Bilayer Revealed by a Universal Machine‐Learning Potential

The recent synthesis of penta‐PdTe 2 sheet highlights the growing interest in pentagonal topologies for developing new 2D materials. Distinct from previously synthesized 2D pentagonal materials, penta‐PdTe 2 possesses the heaviest elemental composition to date, rendering its phonon transport properties particularly intriguing. In this study, the universal machine‐learning potential, NEP89, is fine‐tuned using high‐accuracy first‐principles data spanning monolayer, bilayer, and twisted configurations of penta‐PdTe 2 and achieving an energy prediction error within 2.3 meV atom −1 . Leveraging the homogeneous non‐equilibrium molecular dynamics simulations with the fine‐tuned machine‐learning potential and Wigner transport theory, the phonon transport behavior and lattice thermal conductivity is systematically investigated. These results reveal that interlayer stacking reduces the bilayer thermal conductivity to 28.00% of the monolayer value, while interlayer twisting induces a further reduction to 76.19%, leading to an ultralow thermal conductivity of (0.30 ± 0.059) W m −1 K −1 . These findings demonstrate that the interplay of pentagonal topology, strategic elemental composition, and twist engineering provides an effective route for tuning phonon transport in 2D materials.