Ultrahigh Thermal Conductivity in Isotopically Ultrapure Single-Crystal Diamond
Abstract
Diamond has the highest thermal conductivity among natural materials. Reducing isotope scattering can further push the limit of thermal conductivity of diamond. Here, we report the room-temperature thermal conductivity of a diamond single crystal with an exceptionally low ppm-level 13C content. Secondary ion mass spectrometry (SIMS) reveals a 13C concentration of only ~0.00024% and negligible other impurities, placing this sample as the most isotopically purified diamond samples reported to date. Time-domain thermoreflectance measurements show a room-temperature thermal conductivity of ~3100 W m-1 K-1. Although this value is markedly higher than that of natural diamond, it remains comparable to the best reported values for less isotopically 12C pure diamond. This result suggests that additional phonon-scattering mechanisms beyond isotope scattering may exist at this extreme isotopic purification level. Vacancy defects may contribute to the remaining suppression of thermal conductivity.
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BibTeX
@misc{liu2026ultrahigh,
title = {{Ultrahigh Thermal Conductivity in Isotopically Ultrapure Single-Crystal Diamond}},
author = {Jinwen Liu and Junliang Fan and Zifeng Huang and Zhe Cheng},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.24191},
eprint = {2609.24191},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.24191},
}
RIS
TY - UNPB
TI - Ultrahigh Thermal Conductivity in Isotopically Ultrapure Single-Crystal Diamond
AU - Jinwen Liu
AU - Junliang Fan
AU - Zifeng Huang
AU - Zhe Cheng
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.24191
UR - https://arxiv.org/abs/2609.24191
AB - Diamond has the highest thermal conductivity among natural materials. Reducing isotope scattering can further push the limit of thermal conductivity of diamond. Here, we report the room-temperature thermal conductivity of a diamond single crystal with an exceptionally low ppm-level 13C content. Secondary ion mass spectrometry (SIMS) reveals a 13C concentration of only ~0.00024% and negligible other impurities, placing this sample as the most isotopically purified diamond samples reported to date. Time-domain thermoreflectance measurements show a room-temperature thermal conductivity of ~3100 W m-1 K-1. Although this value is markedly higher than that of natural diamond, it remains comparable to the best reported values for less isotopically 12C pure diamond. This result suggests that additional phonon-scattering mechanisms beyond isotope scattering may exist at this extreme isotopic purification level. Vacancy defects may contribute to the remaining suppression of thermal conductivity.
ER -