Researchers from C2N and collaborators at Neel lab., MPQ lab, L2C lab. and Kansas university report record thermal transport properties in isotopically purified hexagonal boron nitride (hBN), a two-dimensional insulating material of major interest for thermal dissipation and thermal anisotropy. By combining microfabricated suspended devices with Raman thermometry (Fig a and b), the team demonstrates an in-plane thermal conductivity exceeding 1650 W·m⁻¹·K⁻¹ at room temperature, among the highest values ever measured for hBN.
Moreover, the study reveals that heat transport in these materials strongly deviate from the classical Fourier diffusion law (Fig c). While temperature profiles remain linear at high temperature, they become clearly nonlinear at lower temperatures, highlighting the emergence of non-classical regime as describe by the Fourier law and possibly hydrodynamic phonon transport regimes.
This work also introduces a robust experimental framework to accurately measure thermal conductivity in 2D materials, emphasizing the importance of spatial temperature mapping and of the measurement technic itself. Beyond fundamental insights, these results open new perspectives for thermal management technologies and for the development of thermal devices such as diodes, rectifiers, and logic components based on phonon transport.
Références
Extreme longitudinal thermal conductivity and non-diffusive heat transport in isotopic hBN
C. Brochard-Richard1, G. Di Berardino1, E. Herth1, C. Wei1, F. Panciera1, T. Poirier2, J. H. Edgar2, B. Gil3, G. Cassabois3, M. L. Della Rocca4, S. Sarkar5, N. Bendiab5, L. Marty5, F. Oehler1, A. Ouerghi1, J. Chaste1
Nature Communications, (2026).
DOI : https://doi-org.ezproxy.universite-paris-saclay.fr/10.1038/s41467-026-69907-x
Affiliations
1Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, 91120, Palaiseau, France.
2Tim Taylor Department of Chemical Engineering, Kansas State University, Durland Hall, Manhattan, KS 66506-5102, USA
3Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, F-34095 Montpellier, France
4Université Paris Cité, CNRS, Laboratoire Matériaux et Phénomènes Quantiques, F-75013, Paris, France
5Université Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL, F-38000, Grenoble, France.
Contact : Julien Chaste
Figure: a) Schematic of the experiment with a 2D heterostructure made of hexagonal Boron Nitride suspended between two microheaters of silicon. b) an optical image of the suspended sample and c) a Temperature cartography along the sample with a nonlinear behavior, in contradiction with a classical thermal transport regime.
