Origins of Pressure-Enhanced Thermal Transport in Organic Semiconductors
Abstract
While pressure is known to dramatically alter the electronic properties of organic semiconductors, its impact on their thermal conductivity remains poorly understood. We combine machine learned potentials with the Wigner transport equation to compute the pressure-dependent thermal conductivity of crystalline naphthalene as a model system. When high-pressure reference data are included in the training, our simulations quantitatively reproduce the experimentally observed dramatic increase in thermal conductivity for compressed naphthalene. Most importantly, our results reveal the microscopic origin of this massive enhancement: pressure stiffens especially the intermolecular bonds, increasing the group velocities of heat-carrying phonons and simultaneously suppressing the scattering that impedes intraband (propagation) thermal transport. In contrast, interband (tunneling) transport is relatively weakened by a reduced spectral overlap between different phonon bands. These findings provide fundamental insights into heat conduction in soft molecular materials and suggest that strengthening intermolecular interactions, here, via applying pressure can be used to tune thermal transport in molecular crystals.
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BibTeX
@misc{legenstein2026origins,
title = {{Origins of Pressure-Enhanced Thermal Transport in Organic Semiconductors}},
author = {Lukas Legenstein and Sandro Wieser and Michele Simoncelli and Egbert Zojer},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.14672},
eprint = {2609.14672},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.14672},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Origins of Pressure-Enhanced Thermal Transport in Organic Semiconductors
AU - Lukas Legenstein
AU - Sandro Wieser
AU - Michele Simoncelli
AU - Egbert Zojer
PY - 2026
DA - 2026/09/13
PB - arXiv
DO - 10.48550/arxiv.2609.14672
UR - https://arxiv.org/abs/2609.14672
AB - While pressure is known to dramatically alter the electronic properties of organic semiconductors, its impact on their thermal conductivity remains poorly understood. We combine machine learned potentials with the Wigner transport equation to compute the pressure-dependent thermal conductivity of crystalline naphthalene as a model system. When high-pressure reference data are included in the training, our simulations quantitatively reproduce the experimentally observed dramatic increase in thermal conductivity for compressed naphthalene. Most importantly, our results reveal the microscopic origin of this massive enhancement: pressure stiffens especially the intermolecular bonds, increasing the group velocities of heat-carrying phonons and simultaneously suppressing the scattering that impedes intraband (propagation) thermal transport. In contrast, interband (tunneling) transport is relatively weakened by a reduced spectral overlap between different phonon bands. These findings provide fundamental insights into heat conduction in soft molecular materials and suggest that strengthening intermolecular interactions, here, via applying pressure can be used to tune thermal transport in molecular crystals.
ER -