The first quaternary rare-earth oxythiogermanate with second-harmonic generation and ferromagnetic behavior

The discovery of new functional materials is attractive since they have the opportunity to change some important fields. Of these materials, oxychalcogenides constitute an increasing type of nonlinear optical (NLO) material. Herein, a new rare-earth oxythiogermanate Eu3GeOS4 crystallizing with a polar orthorhombic Pca2(1) structure is studied. Its three-dimensional structure is constructed from unique [EuOS6] monocapped trigonal prisms and isolated [GeOS3] tetrahedra, featuring a new type of oxysulfides. Its band gap is 2.05 eV, and it exhibits obvious second-harmonic generation (SHG) response and high laser-induced damage threshold. In addition, Eu3GeOS4 exhibits Curie-Weiss ferromagnetic behavior in the high-temperature region. The SHG effect is ascribed to the synergistic effect of [EuOS6] and [GeOS3] units based on theoretical calculation results. This work is the first investigation of quaternary rare-earth oxythiogermanates as NLO materials.

Automated summary

In this study, a new rare-earth oxythiogermanate Eu3GeOS4 with a polar orthorhombic Pca2(1) structure is investigated. It exhibits obvious second-harmonic generation (SHG) response and high laser-induced damage threshold, making it a potential nonlinear optical material. Additionally, Eu3GeOS4 shows Curie-Weiss ferromagnetic behavior in the high-temperature region. The SHG effect is attributed to the synergistic effect of [EuOS6] and [GeOS3] units based on theoretical calculations.