期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2019
卷号：116
期号：40
页码：19869-19874
DOI：10.1073/pnas.1910131116
出版社：The National Academy of Sciences of the United States of America
摘要：Analyses of thermal diffusivity data on complex insulators and on strongly correlated electron systems hosted in similar complex crystal structures suggest that quantum chaos is a good description for thermalization processes in these systems, particularly in the high-temperature regime where the many phonon bands and their interactions dominate the thermal transport. Here we observe that for these systems diffusive thermal transport is controlled by a universal Planckian timescale τ ∼ ℏ / k B T and a unique velocity v E . Specifically, v E ≈ v p h for complex insulators, and v p h ≲ v E ≪ v F in the presence of strongly correlated itinerant electrons ( v p h and v F are the phonon and electron velocities, respectively). For the complex correlated electron systems we further show that charge diffusivity, while also reaching the Planckian relaxation bound, is largely dominated by the Fermi velocity of the electrons, hence suggesting that it is only the thermal (energy) diffusivity that describes chaos diffusivity..
