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Materials with an extreme lattice thermal conductivity (κ) are indispensable for thermal energy management applications. Layered materials provide an avenue for designing such functional materials due to their intrinsic bonding heterogeneity. Therefore, a microscopic understanding of the crystal structure, bonding, anharmonic lattice dynamics, and phonon transport properties is critically important for layered materials. Alkaline-earth halofluorides exhibit anisotropy from their layered crystal structure, which is strongly determined by axial bond(s), and it is attributed to the large axial ratio (/ > 2) for CaBrF, CaIF, and SrIF, in which Br/I acts as a rattler, as evidenced from potential energy curves and phonon density of states. The low axial (/) ratio leads to relatively isotropic κ values in the BaXF (X = Cl, Br, I) series. MXF (M = Ca, Sr, Ba) compounds exhibit highly anisotropic (a large phonon transport anisotropy ratio of 10.95 for CaIF) to isotropic (a small phonon transport anisotropy ratio of 1.49 for BaBrF) κ values despite their iso-structure. Moreover, ultralow κ (<1 W/m K) values have been predicted for CaBrF, CaIF, and SrIF in the out-of-plane direction due to weak van der Waals (vdWs) bonding. Overall, this comprehensive study on MXF compounds provides insights into designing low κ layered materials with a large axial ratio by fine-tuning out-of-plane bonding from ionic to vdWs bonding.
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http://dx.doi.org/10.1021/acs.inorgchem.3c03951 | DOI Listing |
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September 2025
Phonon Engineering Research Center of Jiangsu Province, Center for Quantum Transport and Thermal Energy Science, Institute of Physics Frontiers and Interdisciplinary Sciences, School of Physics and Technology, Nanjing Normal University, Nanjing, 210023, China.
As a 2D material with distinctive ferroelectric properties, InSe offers significant potential for the applications in information memory and advanced data storage technologies. It also exhibits a complex phase diagram that is highly sensitive to temperature and pressure variations, resulting in diverse lattice configurations. While extensive studies have focused on the phase transition behavior of InSe, its impact on phonon transport remains largely unexplored.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2025
Plasmonics and Perovskites Laboratory, Department of Materials Science and Engineering, IIT Kanpur, Kanpur, U.P. 208016, India.
Contrary to the state-of-the-art thermoelectrics, such as tellurides and selenides, the thermoelectric performance of earth-abundant and less toxic BiS has been found to be inferior primarily because of poor electron transport. Herein, a less explored approach of composite formation using nanoinclusions of two-dimensional (2D) MXene, a graphene-analogous material, in BiS has been adopted to tailor the transport properties in order to obtain enhanced thermoelectric figure of merit (). Highly conductive stacked sheets of TiCT MXene, incorporated into the matrix of BiS, facilitate smoother electron transport, resulting in significantly enhanced electrical conductivity.
View Article and Find Full Text PDFACS Nano
September 2025
College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, China.
The confining walls made by 2D materials are often considered solid boundary conditions in studies of fluid transport through nanochannels, while the atomically thin walls inherently exhibit thermal fluctuations at a finite temperature. In this work, we investigate the solid-liquid interfacial friction properties of water confined within flexible nanochannels using machine-learning-potential molecular dynamics. Surprisingly, we find that the friction coefficient (λ) increases with lateral size in the flexible nanochannels, following a linear relationship with 1/, which is absent in rigid channels.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2025
School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Here, Pb/Y codoped SnSe nanorods were fabricated via a bottom-up, cost-effective hydrothermal method. The formation of nanorod structures generating high-density grain boundaries significantly enhances phonon scattering, serving as the primary mechanism for lattice thermal conductivity reduction. Furthermore, Y-element enrichment regions, nanoprecipitates, and dense dislocation networks provide additional phonon scattering that further suppresses phonon transport.
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September 2025
Institute of High Pressure Physics, School of Physical Science and Technology, Ningbo University, Ningbo, 315211, China.
Fundamentally understanding lattice dynamics and thermal transport behavior in liquid-like, partially occupied compounds remains a long-standing challenge in condensed matter physics. Here, the microscopic mechanisms are investigated underlying the ultralow thermal conductivity in ordered/liquid-like CuBiS by combining experimental methods with first-principles calculations. The ordered structure and liquid-like are first experimentally synthesized and characterized, partially Cu-atom occupied CuBiS structure with increasing temperature.
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