Ba ₁₀ Zn ₇ Ga ₆ S ₂₆ : Promising Infrared Nonlinear Optical Crystal Exhibiting a High Laser Damage Threshold

A new infrared nonlinear optical chalcogenide, Ba 10 Zn 7 Ga 6 S 26 , was successfully synthesized via a high‐temperature solid‐state reaction. This compound adopts a non‐centrosymmetric structure, crystallizing in the tetragonal space group I 2 m (No. 121), with a = b = 10.8262(3) Å, c = 20.7789(7) Å, and V = 2435.42(13) ų. Its 3D framework is built from T 2 supertetrahedra, [Zn 2 Ga 2 S 10 ], with [ZnS 4 ] tetrahedra occupying the tunnels and Ba 2+ cations filling the interstitial spaces. Remarkably, Ba 10 Zn 7 Ga 6 S 26 exhibits a wide bandgap of 3.47 eV and an exceptionally high laser damage threshold, reaching 41 times that of the benchmark material AgGaS 2 under a 1.064 μm laser radiation. Additionally, it shows a nonphase‐matching second‐harmonic generation response behavior under a 2.10 μm incident laser, with the highest intensity ≈0.3 times that of AgGaS 2 . To further elucidate the optical properties, density functional theory calculations were performed using the VASP software package, providing valuable insights into the relationship between the electronic structure and the observed optical properties.