Ba6In2Ge2Te15: a THz birefringent material with an intriguing quasi-[Te5]4− chain possessing large optical anisotropy and an ultrawide transmission range

Ba 6 In 2 Ge 2 Te 15 , a THz birefringent material with an intriguing quasi-[Te 5 ] 4− chain, was successfully synthesized. Experimental and theoretical results illustrate that Ba 6 In 2 Ge 2 Te 15 exhibits large birefringence and ultrawide transparency windows.