Strong second harmonic generation in two-dimensional ferroelectric IV-monochalcogenides
Strong second harmonic generation in two-dimensional ferroelectric IV-monochalcogenides
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DOI：
10.1088/1361-648x/aa8bfc
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发表时间：
2017-11-01
影响因子：
2.7
通讯作者：
Fregoso, Benjamin M.
中科院分区：
文献类型：
--
作者：
Panday, Suman Raj;Fregoso, Benjamin M.
二维铁电体GeS、GeSe、SnS和SnSe有望具有较大的自发面内电极化和增强的移位电流响应。利用密度泛函方法，我们发现这些材料也表现出迄今为止报道的最大有效二次谐波产生。它可以达到高达10 nm V-1的量级，比原型GaAs大一个数量级。为了使这一结果合理化，我们沿着自发偏振方向用一个简单的一维双波段模型来模拟光学响应。在该模型中，二次谐波产生张量与移位电流响应张量成正比。GeS、GeSe、SnS和SnSe的大位移电流和二次谐波响应使它们成为光电子应用中有前途的非线性材料。
The two-dimensional ferroelectrics GeS, GeSe, SnS and SnSe are expected to have large spontaneous in-plane electric polarization and enhanced shift-current response. Using density functional methods, we show that these materials also exhibit the largest effective second harmonic generation reported so far. It can reach magnitudes up to 10 nm V-1 which is about an order of magnitude larger than that of prototypical GaAs. To rationalize this result we model the optical response with a simple one-dimensional two-band model along the spontaneous polarization direction. Within this model the second-harmonic generation tensor is proportional to the shift-current response tensor. The large shift current and second harmonic responses of GeS, GeSe, SnS and SnSe make them promising non-linear materials for optoelectronic applications.