The Boltzmann transport equation based on third-order anharmonic scattering is widely used to predict the thermal conductivity of material lattices, often obtaining results that agree with experimental measurements. Recently, the important role of high-order anharmonic phonon–phonon interactions has been revealed in several materials, such as cubic boron arsenide (BAs), in which the wide phononic energy gap is found to be a critical factor causing the importance of four-phonon scattering. In this work, by solving the Boltzmann transport equation, we show that the four-phonon scattering has a significant impact on the thermal transport in honeycomb structured monolayer BAs (m-BAs) and its hydrogenated bilayer counterparts (bi-BAs) [Fig. 1(d)]. The lattice thermal conductivity (κL) values of all these structures are reduced after considering four-phonon scattering.

Heat conduction in low-dimensional materials has attracted recent interests for the applications in thermal management and thermoelectrics. Among them, periodic structures have been extensively investigated recently due to the wave-particle duality of phonons. For the multilayer structures under the same system length and interface density, the periodic arrangement of interfaces in perfect SL structure seems to be the best option for heat conduction, since a suppressed thermal transport has been observed in various studies when introducing randomness to the perfect periodic structures due to the emergence of phonon localization.

Phonons, i.e., quanta of vibrational waves, are commonly considered as one of the fundamental quasiparticles, simultaneously exhibiting wave- and particlelike characteristics in nanostructured crystals or bulk materials. The wavelike behavior of phonons impacts thermal properties via coherence mechanisms, as highlighted by several pioneering and recent works.

On 8 October 2022, SCIENTIA SINICA Physica, Mechanica & Astronomica (SCPMA) published online a review entitled "Emerging theory and phenomena in A selective review" is published online in SCPMA. The article provides a comprehensive overview of the emerging theories and novel phenomena in thermal conduction in the last decade or so from the perspective of theoretical models and experimental advances.

Recently, Professor Jie Chen's team in the School of Physical Sciences and Engineering published a review article entitled "Phonon physics in twisted two-dimensional materials" in Applied Physics Letters, a prestigious journal of the American Physical Society.

In August, Professor Jie Chen's group at the Centre for Phononics in the School of Physical Sciences and Engineering published a paper, entitled "How hydrodynamic phonon transport determines the convergence of thermal conductivity in two-dimensional materials", focuses on and explains the special transport of phonons in two-dimensional materials and the difficulty of convergence of thermal conductivity.

On 29 April, Professor Chen Jie's team at the Centre for Phononics in the School of Physical Sciences and Engineering and his collaborators published a research paper entitled "How coherence is governing diffuson heat transfer in amorphous solids" online in npj Computational Materials, developing an important theory to describe heat transport in amorphous materials.

On 22 April 2022, Reviews of Modern Physics published online a full-length review entitled "Interfacial Thermal Resistance: Past, Present and Future". A full-length review (50 pages). The authors are Prof. Jie Chen and Prof. Xiangfan Xu from the School of Physical Science and Engineering/Centre for Phononics and Thermal Sciences, Tongji University, Prof. Jun Zhou from the Centre for Quantum Transport and Thermal Sciences, Nanjing Normal University, and Prof. Baowen Li from the Department of Materials Science and Engineering and the Department of Physics, Southern University of Science and Technology, respectively.

On 4 April 2022, Professor Jie Chen's group at the Centre for Research in Acoustics and Thermal Energy in the School of Physical Sciences and Engineering published a paper entitled "Enhancement of the lattice thermal conductivity of two-dimensional functionalized MXenes by inversion symmetry breaking" was published in Physical Review B. (Shuang Lu, a 2022 PhD student, is the first author of the paper, and Prof. Jie Chen is the corresponding author）

Professor Jie Chen's group recently published a paper entitled "Accurate description of high-order phonon anharmonicity and lattice thermal conductivity from molecular dynamics simulations with machine learning potential".