Uncovering electron-phonon scattering and phonon dynamics in type-I Weyl semimetals
Uncovering electron-phonon scattering and phonon dynamics in type-I Weyl semimetals
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DOI：
10.1103/physrevb.100.220301
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发表时间：
2019-12-24
影响因子：
3.7
通讯作者：
Narang, Prineha
中科院分区：
文献类型：
--
作者：
Coulter, Jennifer;Osterhoudt, Gavin B.;Narang, Prineha
拓扑半金属的研究揭示了跨越极端磁阻效应和超高迁移率的壮观输运现象。由于声子动力学和电子-声子散射在电和热输运中起着关键作用，我们追求对i型Weyl半金属NbAs和TaAs中这些效应的基本理解。在NbAs的温度依赖拉曼光谱中，我们揭示了一个以前未报道的法诺线形状，这是一个源于电子-声子相互作用的特征。此外，NbAs和TaAs中A(1)声子线宽的温度依赖性强烈偏离非谐波衰变的标准模型。为了捕捉导致观察到的Fano不对称和非典型声子线宽的机制，我们提出了由于电子-声子相互作用引起的声子自能校正的第一性原理计算。通过对这些Weyl半金属中的声子动力学和电子-声子相互作用的研究，我们考虑了可能有助于其宏观输运性质的特定微观途径。
Studies of topological semimetals have revealed spectacular transport phenomena spanning extreme magnetoresistance effects and ultrahigh mobilities. As phonon dynamics and electron-phonon scattering play a critical role in the electrical and thermal transport, we pursue a fundamental understanding of these effects in type-I Weyl semimetals NbAs and TaAs. In the temperature-dependent Raman spectra of NbAs we reveal a previously unreported Fano line shape, a signature stemming from the electron-phonon interaction. Additionally, the temperature dependence of the A(1) phonon linewidths in both NbAs and TaAs strongly deviate from the standard model of anharmonic decay. To capture the mechanisms responsible for the observed Fano asymmetry and the atypical phonon linewidth, we present first-principles calculations of the phonon self-energy correction due to the electron-phonon interaction. Through this study of the phonon dynamics and electron-phonon interaction in these Weyl semimetals, we consider specific microscopic pathways which could contribute to the nature of their macroscopic transport.