Improved Birefringence Activated by Tetrahedra Decorated with a Single Linear Unit

Wenlong Xie; Fuming Li; Jianbang Chen; Zhihuang Yang; Guangmao Li; Shilie Pan

doi:10.1002/anie.202307895

Improved Birefringence Activated by Tetrahedra Decorated with a Single Linear Unit

Angew Chem Int Ed Engl. 2023 Aug 21;62(34):e202307895. doi: 10.1002/anie.202307895. Epub 2023 Jul 17.

Authors

Wenlong Xie¹, Fuming Li^{1

2}, Jianbang Chen¹, Zhihuang Yang^{1

2}, Guangmao Li^{1

2}, Shilie Pan^{1

2}

Affiliations

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.

PMID: 37382564
DOI: 10.1002/anie.202307895

Abstract

Performance 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 K₂ BaGeS₄ and K₂ BaGeS₅ , 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 K₂ BaGeS₅ (0.19 vs 0.03 of K₂ BaGeS₄ ). This work provides a new guiding thought to improve the birefringence performance.

Keywords: Birefringence; Crystal Engineering; Polarization Anisotropy; Tetrahedra Modification; Thiogermanate.