Layered oxide B2S2O9 with a deep-ultraviolet band gap and a strong and robust second-harmonic generation

Article

关键词: HEXAGONAL BORON-NITRIDE;    NONLINEAR OPTICS;    SIMULATION;    CRYSTALS;   

DOI  :  10.1103/PhysRevB.102.205424

来源: SCIE

【 摘 要 】

Two-dimensional (2D) layered semiconductors with both ultrawide band gap 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. Here, we predict the B2S2O9 (BSO), an existing layered oxide, can exhibit both DUV band gap and strong SHG effects, among the highest values in all 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 near-zero Poisson 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 materials and applications in the 2D limit.

【 授权许可】

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