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arXiv · 2610.24988

Strong Thermal Conductivity Suppression in Isotope Purified Single Crystal Diamond with Phonon Scatterings of Color Centers

Jinwen Liu·Junliang Fan·Zimu Jiang·Zifeng Huang·Zhe Cheng
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Abstract

The thermal conductivity of natural diamond can be further improved by ~50% by eliminating isotope impurity to obtain pure 12C diamond. However, unlike isolated point defects, how color centers scatter phonons and correspondingly limit the thermal conductivity remain poorly understood. Here, we report the thermal conductivities of two isotope-purified diamond with different Nitrogen-vacancy (NV) color center concentrations, confirmed by photoluminescence (PL) and secondary-ion mass spectrometry (SIMS). Results show ~ 3200 W m-1 K-1 and ~ 2100 W m-1 K-1 for two samples of low and high NV concentrations, respectively. Modified Callaway model analyses show that first-principles-derived scattering parameters can reproduce room-temperature thermal conductivity of the high NV concentration sample under a vacancy concentration assumption (~30% of the total Nitrogen concentration), but fail to reproduce its temperature dependence. Compared to PL and SIMS results, which show ~7.1-fold NV concentration and ~92-fold difference in total Nitrogen concentration between two samples, suggesting the assumed 30% vacancy fraction may be greatly overestimated. Taken together, these results suggest that NV-color-center defects may scatter phonons more strongly than models treating Nitrogen and vacancy as independent point defects, providing new insights into color-center-induced phonon-scattering mechanisms.

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Jinwen Liu, Junliang Fan, Zimu Jiang, Zifeng Huang, Zhe Cheng. 2026-10-18. Strong Thermal Conductivity Suppression in Isotope Purified Single Crystal Diamond with Phonon Scatterings of Color Centers. https://arxiv.org/abs/2610.24988

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