Ba<sub>5</sub>Ga<sub>2</sub>SiO<sub>4</sub>S<sub>6</sub>: a Phase-Matching Nonlinear Optical Oxychalcogenide Design via Structural Regulation Originated from Heteroanion Introduction
Yong‐Fang Shi, Shenghua Zhou, Bingxuan Li, Yi Liu, Xintao Wu, Hua Lin, Qi‐Long Zhu
Abstract
Tailored structural regulation to obtain a new non-centrosymmetric (NCS) compound with excellent optical properties is highly desirable but remains a challenge for nonlinear optical (NLO) material design. In this work, centrosymmetric celsian-type BaGa2Si2O8 was selected as a template structure, and a novel NCS oxychalcogenide, namely, Ba5Ga2SiO4S6, was successfully designed via the introduction of heteroanions under high-temperature solid-state conditions. Ba5Ga2SiO4S6 adopts the monoclinic space group of Cc (no. 9) and is formed by charges balancing Ba2+ cations and discrete [Ga2SiO4S6] clusters made of corner-sharing [SiO4] and [GaOS3] tetrahedra. Notably, Ba5Ga2SiO4S6 exhibits the critical requirements as a potential UV NLO candidate, including a phase-matching second-harmonic generation intensity (∼1.0 × KDP), a beneficial laser-induced damage threshold (1.2 × KDP), a large birefringence (Δn = 0.10@546 nm), and a short UV absorption cutoff edge (ca. 0.26 μm). Furthermore, the theoretical calculation is implemented to provide a deeper analysis of the structure–activity relationship. The investigated example of structural regulation originated from heteroanion introduction in this study may offer a feasible strategy for high-performance NLO candidate design.