论文标题
赤铁矿（$α-fe_ {2} o_ {3} $）中的偏光型光学转变由第一原理电子偶联显示
Polaronic Optical Transitions in Hematite ($α-Fe_{2}O_{3}$) Revealed by First-Principles Electron-Phonon Coupling
论文作者
论文摘要
光吸收后的极化子形成是一个关键过程，它定义了许多半导体过渡金属氧化物的光物理特性，该特性包括具有潜在光电和光催化应用的重要类材料。在这项工作中，我们使用赤铁矿（$α-fe_ {2} o_ {3} $）作为模型过渡金属氧化物半导体，以证明带边缘偏极状态的直接光学群体的可行性。我们在DFT+U+J方法的框架内采用第一原理电子 - 波计算，以在声子位移的热分布中揭示这些状态的存在，并用温度对其演变进行建模。我们的计算重现了赤铁矿的光学介电功能的温度依赖性，其精度很高，并表明带边的光吸收和二阶共振拉曼光谱来自二极化光学跃迁，涉及涉及以大于50 mev的能量的纵向光学声子偶联到纵向光学声子。此外，我们发现所产生的极性子包含一个位于两个相邻的Fe原子的电子，这些电子主要位于沿着沿声子的坐标为31和81 MeV的声子的坐标。
Polaron formation following optical absorption is a key process that defines the photophysical properties of many semiconducting transition metal oxides, which comprise an important class of materials with potential optoelectronic and photocatalytic applications. In this work, we use hematite ($α-Fe_{2}O_{3}$) as a model transition metal oxide semiconductor to demonstrate the feasibility of direct optical population of band-edge polaronic states. We employ first-principles electron-phonon computations within the framework of the DFT+U+J method to reveal the presence of these states within a thermal distribution of phonon displacements and model their evolution with temperature. Our computations reproduce the temperature dependence of the optical dielectric function of hematite with remarkable accuracy and indicate that the band-edge optical absorption and second-order resonance Raman spectra arise from polaronic optical transitions involving coupling to longitudinal optical phonons with energies greater than 50 meV. Additionally, we find that the resulting polaron comprises an electron localized to two adjacent Fe atoms with distortions that lie primarily along the coordinates of phonons with energies of 31 and 81 meV.
