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Abstract Polarimetric infrared (IR) detection bolsters IR thermography by leveraging the polarization of light. Optical anisotropy, i.e., birefringence and dichroism, can be leveraged to achieve polarimetric detection. Recently, giant optical anisotropy is discovered in quasi‐1D narrow‐bandgap hexagonal perovskite sulfides, A1+xTiS3, specifically BaTiS3and Sr9/8TiS3. In these materials, the critical role of atomic‐scale structure modulations in the unconventional electrical, optical, and thermal properties raises the broader question of the nature of other materials that belong to this family. To address this issue, for the first time, high‐quality single crystals of a largely unexplored member of the A1+xTiX3(X = S, Se) family, BaTiSe3are synthesized. Single‐crystal X‐ray diffraction determined the room‐temperature structure with theP31cspace group, which is a superstructure of the earlier reportedP63/mmcstructure. The crystal structure of BaTiSe3features antiparallelc‐axis displacements similar to but of lower symmetry than BaTiS3, verified by the polarization dependent Raman spectroscopy. Fourier transform infrared (FTIR) spectroscopy is used to characterize the optical anisotropy of BaTiSe3, whose refractive index along the ordinary (E⊥c) and extraordinary (E‖c) optical axes is quantitatively determined by combining ellipsometry studies with FTIR. With a giant birefringence Δn∼ 0.9, BaTiSe3emerges as a new candidate for miniaturized birefringent optics for mid‐wave infrared to long‐wave infrared imaging.
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Molten flux growth of single crystals of quasi-1D hexagonal chalcogenide BaTiS3
Abstract BaTiS3, a quasi-1D complex chalcogenide, has gathered considerable scientific and technological interest due to its giant optical anisotropy and electronic phase transitions. However, the synthesis of high-quality BaTiS3crystals, particularly those featuring crystal sizes of millimeters or larger, remains a challenge. Here, we investigate the growth of BaTiS3crystals utilizing a molten salt flux of either potassium iodide, or a mixture of barium chloride and barium iodide. The crystals obtained through this method exhibit a substantial increase in volume compared to those synthesized via the chemical vapor transport method, while preserving their intrinsic optical and electronic properties. Our flux growth method provides a promising route toward the production of high-quality, large-scale single crystals of BaTiS3, which will greatly facilitate advanced characterizations of BaTiS3and its practical applications that require large crystal dimensions. Additionally, our approach offers an alternative synthetic route for other emerging complex chalcogenides. Graphical Abstract
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- PAR ID:
- 10523112
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Journal of Materials Research
- ISSN:
- 0884-2914
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1557/s43578-024-01379-5
