First-Principles Study on Thermal and Electrical Transport Properties of NbGe_(2) and NbSi_(2):The Role of Electron-Phonon Coupling  

作　　者：Gui-Lin Zhu Man-Yu Shang Jing-Tao Lu 

机构地区：[1]School of Physics,Institute for Quantum Science and Engineering and Wuhan National High Magnetic Field Center,Huazhong University of Science and Technology,Wuhan 430074,China [2]College of Science,China Jiliang University,Hangzhou 310018,China

出　　处：《Chinese Physics Letters》2024年第12期107-120,共14页中国物理快报（英文版）

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).

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.

关 键 词：PHONON CONDUCTIVITY ELECTRICAL 

分 类 号：O469[理学—凝聚态物理]