论文标题
非绝热效应在电子带隙的零点重归其化中占主导地位
Predominance of non-adiabatic effects in zero-point renormalization of the electronic band gap
论文作者
论文摘要
材料的电子和光学特性受原子运动的影响，通过电子 - 音波相互作用：不仅带隙随温度而变化，而且即使在绝对零温度下，零点运动也会导致带间隙的恢复。我们提出了超出绝热近似值的带边缘零点重归其化的大规模第一原理评估。对于具有光元素的材料，带隙重新归一化通常大于0.3 eV，最高为0.7 eV。如果寻求准确的频带差距，则不能忽略此效果。对于红外活动材料，仅当考虑到非绝热效应时才能获得与可用实验数据的全球一致性。正如广义的Fröhlich模型所示，它们甚至主导了许多材料的零点重归其化，该模型包括多个声子分支，各向异性和退化电子极值，其有效性范围是通过与第一原则结果相比建立的。
Electronic and optical properties of materials are affected by atomic motion through the electron-phonon interaction: not only band gaps change with temperature, but even at absolute zero temperature, zero-point motion causes band-gap renormalization. We present a large-scale first-principles evaluation of the zero-point renormalization of band edges beyond the adiabatic approximation. For materials with light elements, the band gap renormalization is often larger than 0.3 eV, and up to 0.7 eV. This effect cannot be ignored if accurate band gaps are sought. For infrared-active materials, global agreement with available experimental data is obtained only when non-adiabatic effects are taken into account. They even dominate zero-point renormalization for many materials, as shown by a generalized Fröhlich model that includes multiple phonon branches, anisotropic and degenerate electronic extrema, whose range of validity is established by comparison with first-principles results.
