Pb2TiOF(SeO3)2Cl and Pb2NbO2(SeO3)2Cl: small changes in structure induced a very large SHG enhancement

Abstract

The replacement of NbO₆ octahedra in Pb₂NbO₂(SeO₃)₂Cl by the TiO₅F octahedra in Pb₂TiOF(SeO₃)₂Cl induced a very large SHG enhancement from 2.3 × to 9.6 × KDP (KH₂PO₄), and both materials are type-I phase matchable. Theoretical calculations based on DFT methods indicate that the inclusion of F⁻ anions in the d⁰-TM octahedral coordination unit has a great impact on the band structure and the SHG enhancement of the material.