Pressure-induced phase transition and band-gap decrease in semiconducting Na3Bi(IO3)6
We report a combined experimental/theoretical high-pressure study of NaBi(IO) under compression to 11.2 GPa at ambient temperature. Through a combination of single-crystal and powder synchrotron X-ray diffraction, optical absorption measurements and ab initio density functional theory calculations w...
| Autores: | , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/349640 |
| Acceso en línea: | http://hdl.handle.net/10261/349640 |
| Access Level: | acceso abierto |
| Palabra clave: | High pressure Matter at extreme conditions New materials Phase transitions Synchrotron X-ray diffraction |
| Sumario: | We report a combined experimental/theoretical high-pressure study of NaBi(IO) under compression to 11.2 GPa at ambient temperature. Through a combination of single-crystal and powder synchrotron X-ray diffraction, optical absorption measurements and ab initio density functional theory calculations we unambiguously show a first-order pressure-induced phase transition at around 9.5 GPa from the ambient pressure phase, referred to here as α-NaBi(IO), to a new crystalline structure referred to here as β-NaBi(IO). The triclinic (P-1) to triclinic (P1) phase transition is characterised by a doubling of the primitive cell volume, whereby the crystallographic b-axis doubles in length, and by a decrease in the volume per formula unit of approximately 3 %. The phase transition is also characterised by an indirect → indirect electronic bandgap decrease of approximately 0.1 eV as measured by absorption spectroscopy (3.44(1) → 3.32(1) eV) and calculated via density functional calculations (2.48 → 2.33 eV). We also report the pressure evolution of the crystal lattice parameters and isothermal compressibility tensor of the ambient pressure phase α-NaBi(IO), which reveals highly anisotropic compressibility and a bulk modulus of 30.4(7) GPa. |
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