AI 中文总结
该研究针对现有非绝热声子自能计算的缺陷，以MgB₂为对象，发现高阶非绝热声子修正可缓解问题，得到更吻合实验的线宽与圆顶状耦合强度温度依赖，揭示高阶非绝热性决定声子谱的温度依赖。
AI 中文摘要
非绝热效应决定耦合声子模的频率和线宽、Kohn异常的形状，且对多种材料性质有重要影响。现有最先进的从头算非绝热声子自能依赖无限电子寿命近似，无法捕捉声子谱的温度依赖，忽略长波带内声子衰变，且声子分裂被夸大。在MgB₂中，我们展示高阶非绝热声子修正如何缓解这些缺陷，得到与实验更吻合的线宽，以及圆顶状的耦合强度温度依赖关系。
英文摘要
Nonadiabatic effects determine the frequency and linewidth of coupled phonon modes, shape of Kohn anomalies and have important implications on many material properties. State-of-the-art ab-initio nonadiabatic phonon self-energy relies on an infinite electron lifetime approximation, which cannot capture the temperature dependence of the phonon spectrum, neglects long-wavelength intraband phonon decay, and exhibits exaggerated phonon splitting. In MgB$_2$, we show how the higher-order nonadiabatic phonon corrections mitigate these deficiencies, yielding linewidths in a closer experimental agreement and a dome-like coupling strength temperature dependence.
