Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices. This work successfully synthesized a new thiophosphate phase of β-Pb3P2S8 through the high-temperature solid-state spontaneous crystallization method. Different from the cubic α-Pb3P2S8, the β-Pb3P2S8 crystallizes in the orthorhombic Pbcn space group. Notably, β-Pb3P2S8 shows a large band gap of 2.37 eV in lead-based chalcogenides, wide infrared transparent window (2.5−15 µm), and excellent thermal stability. Importantly, the experimental birefringence shows the largest value of 0.26@550 nm in chalcogenides, even larger than the commercialized oxide materials. The Barder charge analysis result indicates that the exceptional birefringence effect is mainly from the Pb2+ and S2− in the [PbSn] polyhedrons. Meanwhile, the parallelly arranged polyhedral layers could improve the structural anisotropic. Therefore, this work supports a new method for designing chalcogenides with exceptional birefringence effect in the infrared region.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |