Disconnection Enhances the Second Harmonic Generation Response: Synthesis and Characterization of Ba_(23)Ga_8Sb_2S_(38)

摘要

An unusual zero-dimensional quaternary sulfide, Ba_(23)Ga_8Sb_2S_(38), that crystallizes in the non centrosymmetric polar space group Cmc2_1 was discovered by solid-state reaction of an elemental mixture. The involvement of a second building unit consisting of SbS_3 pyramid and constituting 20% of the structure helped to realize the disconnection of the asymmetric GaS_4 tetrahedra. Such a disconnection leads to the strongest powder second harmonic generation intensity in the IR region among sulfides to date, ～22 times that of commercial AgGaS_2 at an incident laser wavelength of 2.05 μm with the same particle size of 46-74 μm.