论文标题
cubr $ _ \ mathrm {x} $ i $ _ {1- \ mathrm {x}} $合金薄膜的介电函数
Dielectric function of CuBr$_\mathrm{x}$I$_{1-\mathrm{x}}$ alloy thin films
论文作者
论文摘要
我们研究CUBR $ _ \ MATHRM {X} $ i $ _ {1- \ MATHRM {X}} $薄膜合金的介电函数，在光谱范围内使用光谱范围为0.7 eV到6.4 eV的光谱椭圆形，与基于密度密度功能理论的结合，在6.4 eV之间进行了计算。通过比较理论和实验，我们将介电函数中的特征归因于布里渊区的特定K点的电子过渡。根据不同的物理和化学贡献，讨论了观察到的带隙作为合金组成的函数。发现由于自旋轨道耦合而导致的价带顶部的频带分裂会随着BR浓度的增加而降低，从CUI的660 MeV值到CUBR的150 MeV。考虑到铜D轨道对合金组成的函数的铜D轨道对价最大值的贡献，可以理解该结果。
We study the dielectric function of CuBr$_\mathrm{x}$I$_{1-\mathrm{x}}$ thin film alloys using spectroscopic ellipsometry in the spectral range between 0.7 eV to 6.4 eV, in combination with first-principles calculations based on density functional theory. Through the comparison of theory and experiment, we attribute features in the dielectric function to electronic transitions at specific k-points in the Brillouin zone. The observed bandgap bowing as a function of alloy composition is discussed in terms of different physical and chemical contributions. The band splitting at the top of the valence band due to spin-orbit coupling is found to decrease with increasing Br-concentration, from a value of 660 meV for CuI to 150 meV for CuBr. This result can be understood considering the contribution of copper d-orbitals to the valence band maximum as a function of the alloy composition.
