AI 中文总结
本研究提出考虑有限寿命声子退相的电子-声子相互作用理论，通过第一性原理计算发现非简谐退相显著增强MgB₂的电子散射率、抑制其电导率，为研究其他材料的相关性质提供了基础。
AI 中文摘要
电子-声子相互作用是诸多材料性质的基础，例如金属的电导率和半导体的光电响应。电子-声子相互作用的第一性原理计算是定量描述日益复杂材料中诸多这类性质的有力工具。然而，所有这类计算都有一个关键假设：声子具有无限寿命，当非简谐声子-声子相互作用较强时，该近似可能失效。本研究提出了电子与具有退相的有限寿命声子相互作用的理论，通过该理论的第一性原理实现，发现非简谐退相会显著增强金属MgB₂中的电子-声子散射率。从微观角度看，声子-声子相互作用会产生新的散射通道，增加电子-声子散射可用的相空间。因此，非简谐退相会强烈抑制MgB₂的电导率，在玻尔兹曼输运方程框架内，使计算值与实验值大幅接近。该实例确立了有限声子寿命在评估电子-声子散射中的重要性，其微观机制表明非简谐退相可能在许多金属的电导率中发挥重要作用。更广泛地说，本研究的理论及电子-声子相互作用中非简谐退相的第一性原理实现，为探索其他材料的该机制提供了坚实基础。
英文摘要
The electron-phonon interaction underpins many material properties, for example, the conductivity of metals and the optoelectronic response of semiconductors. First-principles calculations of the electron-phonon interaction are a powerful tool to quantitatively describe many of these properties in increasingly complex materials. However, one key assumption of all calculations is that phonons have infinite lifetimes, an approximation that may break down when anharmonic phonon-phonon interactions are strong. In this work, we present a theory for the interaction of electrons with finite-lifetime phonons experiencing dephasing. Using a first-principles implementation of the theory, we find that anharmonic dephasing dramatically enhances electron-phonon scattering rates in metallic MgB2. Microscopically, phonon-phonon interactions create new scattering channels that increase the phase space available for electron-phonon scattering. As a result, anharmonic dephasing strongly suppresses conductivity in MgB2, bringing the calculated values substantially closer to experiment within the Boltzmann transport equation framework. This example establishes the importance of finite phonon lifetimes in the evaluation of electron-phonon scattering, and the microscopic mechanism suggests that anharmonic dephasing could play an important role in the conductivity of many metals. More broadly, our theory and first-principles implementation of anharmonic dephasing in the electron-phonon interaction provides a solid foundation to explore this regime in other materials.
Journal refPhys. Rev. B 114, L080304 (2026)
