Characterizations and Nonlinear-Optical Properties of Pentanary Transition-Metal Oxysulfide Sr<sub>2</sub>CoGe<sub>2</sub>OS<sub>6</sub>
Nan Zhang, Qian-Ting Xu, Zhi‐Hui Shi, Mei Yang, Sheng‐Ping Guo
Abstract
As one type of material containing multiple anions, oxysulfides can combine the advantages of oxides and sulfides and are deeply studied as nonlinear-optical (NLO) materials. Herein, a new melilite-type pentanary oxysulfide Sr2CoGe2OS6 is studied. It crystallizes in the noncentrosymmetric tetragonal space group P4̅21m, and its structure features GeOS3 and CoS4 tetrahedra-built {[CoGe2OS6]4–}∞ layers. Its powder sample exhibits a moderate phase-matchable NLO response and a high laser-induced damage threshold. The NLO response is mainly determined by CoS4 tetrahedra according to the theoretical calculation results. This work indicates that transition-metal oxysulfides can also be considered as potential infrared NLO materials.