Affiliation:
1. Research Center for Crystal Materials CAS Key Laboratory of Functional Materials and Devices for Special Environments Xinjiang Technical Institute of Physics & Chemistry, CAS 40-1 South Beijing Road Urumqi 830011 China
2. Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China
Abstract
AbstractPerformance enhancement induced by structural modification has long been the target in materials science fields. Direct evidence to witness the effectivity of one strategy is challenging and necessary. In this work, a tetrahedra‐decoration strategy was proposed to improve the birefringent performance sharply, namely decorating the tetrahedra with a single linear [S2] unit. The strategy was verified by comprehensive characterization of two thiogermanates K2BaGeS4 and K2BaGeS5, which crystallize in the same space group, have similar unit cells and the same units arrangements. Theoretical characterization verified that the [GeS5] group has much larger polarization anisotropy than [GeS4], further demonstrated that the linear [S2] led to the sharp birefringence enlargement of K2BaGeS5 (0.19 vs 0.03 of K2BaGeS4). This work provides a new guiding thought to improve the birefringence performance.