Large Bulk Photovoltaic Effect and Spontaneous Polarization of Single-Layer Monochalcogenides
Large Bulk Photovoltaic Effect and Spontaneous Polarization of Single-Layer Monochalcogenides
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DOI：
10.1103/physrevlett.119.067402
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发表时间：
2017-08-08
影响因子：
8.6
通讯作者：
Neaton, Jeffrey B.
中科院分区：
文献类型：
--
作者：
Rangel, Tonatiuh;Fregoso, Benjamin M.;Neaton, Jeffrey B.
我们采用第一性原理密度泛函理论方法计算了单层Ge和Sn单硫族化合物在均匀光照下的位移电流和线性吸收。我们预测在可见光谱中的强吸收和大的有效三维位移电流（类似于100 μ A/V-2），大于先前在其他极性系统中观察到的。此外，我们表明，位移电流张量的积分与大的自发有效三维电极化（类似于1.9 C/m（2））。我们的计算表明，移动电流将是最大的可见光谱，这表明这些单硫族化合物可能是有前途的极性光电器件。一个水稻梅莱紧束缚模型是用来合理化的移位电流响应这些系统，其依赖于极化，一般而言，与其他极性材料的影响。
We use a first-principles density functional theory approach to calculate the shift current and linear absorption of uniformly illuminated single-layer Ge and Sn monochalcogenides. We predict strong absorption in the visible spectrum and a large effective three-dimensional shift current (similar to 100 mu A/V-2), larger than has been previously observed in other polar systems. Moreover, we show that the integral of the shift-current tensor is correlated to the large spontaneous effective three-dimensional electric polarization (similar to 1.9 C/m(2)). Our calculations indicate that the shift current will be largest in the visible spectrum, suggesting that these monochalcogenides may be promising for polar optoelectronic devices. A Rice-Mele tight-binding model is used to rationalize the shift-current response for these systems, and its dependence on polarization, in general terms with implications for other polar materials.