Phonon-Localization-Driven Decoupling of Dual-Channel Transport for Record-Low Intrinsic Lattice Thermal Conductivity
Abstract
A fundamental bottleneck in pushing the intrinsic lattice thermal conductivity of inorganic crystalline solids to its lowest limit arises from the inherent competition between the particle-like propagation (κLP) and wave-like tunneling (κLC) channels. Herein, we demonstrate that phonon localization provides a robust pathway to decouple the dual-channel transport, achieving record-low κL in quasi-1D ternary helical crystals. Despite the structural complexity leading to densely populated phonon branches and thus inducing abundant coherent phonons, the weak interchain interactions and heavy elements compress numerous branches into highly localized, nearly dispersionless flat bands. Such strong localization simultaneously suppresses both the diagonal and off-diagonal components of the group velocity, thereby synergistically suppressing κLP and κLC. Taking InSeI as an example, the interchain room-temperature κLP and κLC are 0.145 and 0.053 W/mK, respectively, yielding an ultralow total κL of 0.198 W/mK. Weaker interchain interactions further drive the room-temperature κL of GaSeI and AlSeI to record lows of 0.086 and 0.089 W/mK, respectively; these values even drop to 0.058 and 0.059 W/mK at 900 K. These findings provide useful insights into exploring the thermal conductivity limit in crystals.
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BibTeX
@misc{tang2026phononlocalizationdriven,
title = {{Phonon-Localization-Driven Decoupling of Dual-Channel Transport for Record-Low Intrinsic Lattice Thermal Conductivity}},
author = {Zhunyun Tang and Xiaoxia Wang and Jin Li and Chaoyu He and Chao Tang and Mingxing Chen and Tao Ouyang},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.29778},
eprint = {2608.29778},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.29778},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Phonon-Localization-Driven Decoupling of Dual-Channel Transport for Record-Low Intrinsic Lattice Thermal Conductivity
AU - Zhunyun Tang
AU - Xiaoxia Wang
AU - Jin Li
AU - Chaoyu He
AU - Chao Tang
AU - Mingxing Chen
AU - Tao Ouyang
PY - 2026
DA - 2026/08/30
PB - arXiv
DO - 10.48550/arxiv.2608.29778
UR - https://arxiv.org/abs/2608.29778
AB - A fundamental bottleneck in pushing the intrinsic lattice thermal conductivity of inorganic crystalline solids to its lowest limit arises from the inherent competition between the particle-like propagation (κ_L^P) and wave-like tunneling (κ_L^C) channels. Herein, we demonstrate that phonon localization provides a robust pathway to decouple the dual-channel transport, achieving record-low κ_L in quasi-1D ternary helical crystals. Despite the structural complexity leading to densely populated phonon branches and thus inducing abundant coherent phonons, the weak interchain interactions and heavy elements compress numerous branches into highly localized, nearly dispersionless flat bands. Such strong localization simultaneously suppresses both the diagonal and off-diagonal components of the group velocity, thereby synergistically suppressing κ_L^P and κ_L^C. Taking InSeI as an example, the interchain room-temperature κ_L^P and κ_L^C are 0.145 and 0.053 W/mK, respectively, yielding an ultralow total κ_L of 0.198 W/mK. Weaker interchain interactions further drive the room-temperature κ_L of GaSeI and AlSeI to record lows of 0.086 and 0.089 W/mK, respectively; these values even drop to 0.058 and 0.059 W/mK at 900 K. These findings provide useful insights into exploring the thermal conductivity limit in crystals.
ER -