Thermal transport in amorphous materials has remained one of the fundamental questions in solid state physics while involving a very large field of applications.Using a heat conduction theory incorporating coherence,w...Thermal transport in amorphous materials has remained one of the fundamental questions in solid state physics while involving a very large field of applications.Using a heat conduction theory incorporating coherence,we demonstrate that the strong phase correlation between local and non-propagating modes,commonly named diffusons in the terminology of amorphous systems,triggers the conduction of heat.By treating the thermal vibrations as collective excitations,the significant contribution of diffusons,predominantly relying on coherence,further reveals interesting temperature and length dependences of thermal conductivity.The propagation length of diffuson clusters is found to reach the micron,overpassing the one of propagons.The explored wavelike behavior of diffusons uncovers the unsolved physical picture of mode correlation in prevailing models and further provides an interpretation of their ability to transport heat.This work introduces a framework for understanding thermal vibrations and transport in amorphous materials,as well as an unexpected insight into the wave nature of thermal vibrations.展开更多
We report a theoretical investigation of coherent-to-incoherent heat conduction in multilayer nanostructures.In the coherent regime where the phonon motion is quasi-harmonic,the elastic continuum model gives accurate ...We report a theoretical investigation of coherent-to-incoherent heat conduction in multilayer nanostructures.In the coherent regime where the phonon motion is quasi-harmonic,the elastic continuum model gives accurate cross-plane thermal conductivity predictions of upper limits and demonstrates that the coherent transport is the result of the interplay between intrinsic wave effects.As the temperature or system size increases,the phonon dephasing scattering results in the deviation of thermal conductivity from the coherent-limit calculation.By further introducing the incoherence of phonons,we reproduce the classical minimum thermal conductivity,indicating the feasibility of extending the pure wave model into the wave-particle crossing regime.展开更多
基金This work is partially supported by CREST JST(No.JPMJCR19I1 and JPMJCR19Q3)This research used the computational resources of the Oakforest-PACS supercomputer system,The University of Tokyo+1 种基金This project is also supported in part by the grants from the National Natural Science Foundation of China(Grant Nos.12075168 and 11890703)Science and Technology Commission of Shanghai Municipality(Grant No.19ZR1478600).
文摘Thermal transport in amorphous materials has remained one of the fundamental questions in solid state physics while involving a very large field of applications.Using a heat conduction theory incorporating coherence,we demonstrate that the strong phase correlation between local and non-propagating modes,commonly named diffusons in the terminology of amorphous systems,triggers the conduction of heat.By treating the thermal vibrations as collective excitations,the significant contribution of diffusons,predominantly relying on coherence,further reveals interesting temperature and length dependences of thermal conductivity.The propagation length of diffuson clusters is found to reach the micron,overpassing the one of propagons.The explored wavelike behavior of diffusons uncovers the unsolved physical picture of mode correlation in prevailing models and further provides an interpretation of their ability to transport heat.This work introduces a framework for understanding thermal vibrations and transport in amorphous materials,as well as an unexpected insight into the wave nature of thermal vibrations.
文摘We report a theoretical investigation of coherent-to-incoherent heat conduction in multilayer nanostructures.In the coherent regime where the phonon motion is quasi-harmonic,the elastic continuum model gives accurate cross-plane thermal conductivity predictions of upper limits and demonstrates that the coherent transport is the result of the interplay between intrinsic wave effects.As the temperature or system size increases,the phonon dephasing scattering results in the deviation of thermal conductivity from the coherent-limit calculation.By further introducing the incoherence of phonons,we reproduce the classical minimum thermal conductivity,indicating the feasibility of extending the pure wave model into the wave-particle crossing regime.
