金属导热理论的研究进展与前沿问题

Recent advances in thermal transport theory of metals

金属是人类使用最广泛的材料之一.相对于对金属力学性能的研究,金属导热性能的相关研究较为匮乏.对金属导热机制的理解往往还依赖于一百多年前建立的威德曼-弗朗兹定律.金属导热和电子输运有密切联系,同时又与晶格振动有关.深入理解金属导热机制,不但对材料应用意义重大,而且有利于提高对导热基本理论的认知.本文回顾了金属导热研究的历史,并对最近十几年来金属导热的研究进行了总结,特别是对基于第一原理电子-声子耦合模式分析的金属导热机理的研究进行了综述.此外,本文也对金属导热理论的未来发展方向进行了探讨.

Metal is one of the most widely used engineering materials.In contrast to the extensive research dedicated to their mechanical properties,studies on the thermal conductivity of metals remain relatively rare.The understanding of thermal transport mechanisms in metals is mainly through the Wiedemann-Franz Law established more than a century ago.The thermal conductivity of metal is related to both the electron transport and the lattice vibration.An in-depth understanding of the thermal transport mechanism in metal is imperative for optimizing their practical applications.This review first discusses the history of the thermal transport theory in metals,including the Wiedemann-Franz law and models for calculating phonon thermal conductivity in metal.The recently developed first-principles based mode-level electron-phonon interaction method for determining the thermal transport properties of metals is briefly introduced.Then we summarize recent theoretical studies on the thermal conductivities of elemental metals,intermetallics,and metallic ceramics.The value of thermal conductivity,phonon contribution to total thermal conductivity,the influence of electronphonon interaction on thermal transport,and the deviation of the Lorenz number are comprehensively discussed.Moreover,the thermal transport properties of metallic nanostructures are summarized.The size effect of thermal transport and the Lorenz number obtained from experiments and calculations are compared.Thermal transport properties including the phonon contribution to total thermal conductivity and the Lorenz number in two-dimensional metals are also mentioned.Finally,the influence of temperature,pressure,and magnetic field on thermal transport in metal are also discussed.The deviation of the Lorenz number at low temperatures is due to the different electron-phonon scattering mechanisms for thermal and electrical transport.The mechanism for the increase of thermal conductivity in metals induced by pressure varies in different kinds of metals and is related to the electron state at the Fermi level.The effect of magnetic field on thermal transport is related to the coupling between the electron and the magnetic field,therefore the electron distribution in the Brillouin zone is an important factor.In addition,this review also looks forward to the future research directions of metal thermal transport theory.