论文标题
深硫酸盐分层氧化物B2S2O9具有强大而坚固的第二谐波生成
Deep-ultraviolet Layered Oxide B2S2O9 with Strong and Robust Second Harmonic Generation
论文作者
论文摘要
具有Ultrawide带隙和强次谐波生成（SHG）的二维（2D）分层半导体对于将非线性光学（NLO）应用扩展到纳米级的深脉度（DUV）区域至关重要。不幸的是，这些材料本质上很少见，直到现在才发现。在这封信中，我们预测B2S2O9（BSO）是一种现有的氧化氧化物，可以表现出DUV BandGap和强烈的SHG效应，与最著名的DUV NLO散装相媲美。 BSO中强的SHG强度源自极性SO4和BO4四面体形成平面结构的有序排列，可通过层厚度线性调节。令人惊讶的是，在菌株下刚性四面体的自发旋转会诱导BSO中（几乎）零泊松的比率，这同时导致对大型菌株的强大SHG效应，与其他已知的2D NLO半导体有根本不同。 BSO的发现可能提供了前所未有的机会，可以在2D限制中探索DUV NLO物理和应用。
Two-dimensional (2D) layered semiconductors with both ultrawide bandgap and strong second harmonic generation (SHG) are essential for expanding the nonlinear optical (NLO) applications to deep-ultraviolet (DUV) region in nanoscale. Unfortunately, these materials are rare in nature and have not been discovered until now. In this Letter, we predict the B2S2O9 (BSO), an existing layered oxide, can exhibit both DUV bandgap and strong SHG effects, comparable to the best known DUV NLO bulks. The strong SHG intensities in BSO, originated from the ordered arrangement of polar SO4 and BO4 tetrahedra forming planar structure, are linearly tunable by the layer thickness. Surprisingly, the spontaneous rotations of rigid tetrahedra under strains can induce the (nearly) zero Poisson's ratios in BSO, which simultaneously result in the robust SHG effects against large strains, fundamentally differing from other known 2D NLO semiconductors. The discovery of BSO may provide an unprecedented opportunity to explore DUV NLO physics and applications in 2D limit.
