Pressure-induced ferroelectric-like transition creates a polar metal in defect antiperovskites Hg
| Autor: | Weizhao, Cai, Jiangang, He, Hao, Li, Rong, Zhang, Dongzhou, Zhang, Duck Young, Chung, Tushar, Bhowmick, Christopher, Wolverton, Mercouri G, Kanatzidis, Shanti, Deemyad |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Nature Communications |
| ISSN: | 2041-1723 |
| Popis: | Ferroelectricity is typically suppressed under hydrostatic compression because the short-range repulsions, which favor the nonpolar phase, increase more rapidly than the long-range interactions, which prefer the ferroelectric phase. Here, based on single-crystal X-ray diffraction and density-functional theory, we provide evidence of a ferroelectric-like transition from phase I213 to R3 induced by pressure in two isostructural defect antiperovskites Hg3Te2Cl2 (15.5 GPa) and Hg3Te2Br2 (17.5 GPa). First-principles calculations show that this transition is attributed to pressure-induced softening of the infrared phonon mode Γ4, similar to the archetypal ferroelectric material BaTiO3 at ambient pressure. Additionally, we observe a gradual band-gap closing from ~2.5 eV to metallic-like state of Hg3Te2Br2 with an unexpectedly stable R3 phase even after semiconductor-to-metal transition. This study demonstrates the possibility of emergence of polar metal under pressure in this class of materials and establishes the possibility of pressure-induced ferroelectric-like transition in perovskite-related systems. Generally, ferroelectricity in ABO3 perovskites is suppressed by hydrostatic compression, but the evidence for pressure-induced ferroelectricity remains elusive. Here, the authors find a direct ferroelectric-like structural transition induced by pressure in defect antiperovskites. |
| Databáze: | OpenAIRE |
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