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Updated: Oct 26, 2025
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Published on: April 9, 2018
Highly Distorted [HgS4] Motif-Driven Structural Symmetry Degradation and Strengthened Second-Harmonic Generation
Wenhao Xing1,2,3, Fei Liang1,3, Chunlan Tang2
1Beijing Center for Crystal Research and Development, Key Lab of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
Abstract:
Chalcogenides with diamond-like (DL) structures are a treasury of infrared nonlinear optical (NLO) materials. Here, a ternary Hg-based chalcogenide with a defect DL structure, Hg3P2S8, is synthesized by solid-state reaction. Driven by the highly distorted [HgS4] tetrahedra, this compound displays an interesting structural symmetry degradation from tetragonal to orthorhombic compared with its analogue Zn3P2S8. Meanwhile, the overall performances of Hg3P2S8 are quite remarkable, including a very strong phase-matchable second-harmonic generation (SHG) response (4.2 × AgGaS2), large band gap (2.77 eV), wide IR transparent range (0.45-16.7 μm), and high laser-induced damage threshold (4 × AGS). Furthermore, the theoretical analysis and local dipole moment calculations elucidate that the highly distorted [HgS4] tetrahedra contribute a lot to the enhancement of the SHG effect. This discovery will motivate the exploration of other DL Hg-based chalcogenides serving as high-performing mid-IR NLO materials.
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