Highly Distorted [HgS4] Motif-Driven Structural Symmetry Degradation and Strengthened Second-Harmonic Generation Response in the Defect Diamond-Like Chalcogenide Hg3P2S8.
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.
['Xing|Wenhao|W|https://orcid.org/0000-0003-1258-419X', 'Liang|Fei|F|https://orcid.org/0000-0002-4932-1329', 'Tang|Chunlan|C|', 'Uykur|Ece|E|https://orcid.org/0000-0001-7253-4579', 'Lin|Zheshuai|Z|https://orcid.org/0000-0002-9829-9893', 'Yao|Jiyong|J|https://orcid.org/0000-0002-4802-5093', 'Yin|Wenlong|W|https://orcid.org/0000-0003-2660-0891', 'Kang|Bin|B|']
symmetry degradation second-harmonic generation chalcogenide infrared nonlinear optical Hg-based diamond-like structure