摘要
We investigate coupled electron and phonon transport in NbX_(2) with X=Ge,Si,where experimental evidence of strong electron-phonon coupling and hydrodynamic transport has been reported.Based on first-principles density functional theory calculations,we measured the thermal and electrical transport properties of the compounds.We found that phonon-electron scattering strongly affects phonon thermal conductivity(κph)and leads to a weak temperature dependence ofκph instead of a normal inverse temperature dependence when anharmonic three-phonon scattering dominates.In addition,κph contributes to a quarter of the total thermal conductivity,which differs from typical metals in which the total thermal conductivity is predominantly derived from electrons.In contrast to previous numerical research,our electrical resistivity results agree well with the experimental measurements.The anisotropic properties of the transport coefficients are attributed to the electron-phonon dispersion relation.In addition,we found a negligible effect of electron-phonon drag on the transport properties,contrary to the expectation from a strongly coupled electron-phonon fluid.
基金
supported in part by the National Natural Science Foundation of China (Grant No. 22273029)
the Natural Science Foundation of Zhejiang Province, China (Grant No. 20230021).
