强二次谐波产生的深紫外层状氧化物B2S2O9
Deep-ultraviolet Layered Oxide B2S2O9 with Strong and Robust Second Harmonic Generation
摘要：
具有超宽带隙和强二次谐波效应的二维层状半导体材料是将非线性光学应用拓展到纳米尺度深紫外波段的关键。不幸的是，这些材料在自然界中很罕见，直到现在才被发现。在这封信中，我们预测B2S2O9（BSO），现有的层状氧化物，可以表现出DUV带隙和强大的SHG效应，与最知名的DUV NLO块。BSO中的强倍频强度来源于极性SO4和BO4四面体的有序排列形成平面结构，并可通过层厚度线性调谐。令人惊讶的是，刚性四面体在应变下的自发旋转可以在BSO中诱导（接近）零的泊松比，这同时导致对大应变的鲁棒SHG效应，与其他已知的2D NLO半导体根本不同。BSO的发现可能为探索二维极限深紫外非线性光学物理及其应用提供了前所未有的机会。
英文摘要：
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.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
