Pressure-induced phase transition and band-gap decrease in semiconducting Na3Bi(IO3)6

Autor: Robin Turnbull, Javier González-Platas, Akun Liang, Dequan Jiang, Yonggang Wang, Catalin Popescu, Plácida Rodríguez-Hernández, Alfonso Muñoz, Jordi Ibáñez, Daniel Errandonea
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Results in Physics, Vol 44, Iss , Pp 106156- (2023)
Druh dokumentu: article
ISSN: 2211-3797
DOI: 10.1016/j.rinp.2022.106156
Popis: We report a combined experimental/theoretical high-pressure study of Na3Bi(IO3)6 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-Na3Bi(IO3)6, to a new crystalline structure referred to here as β-Na3Bi(IO3)6. 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-Na3Bi(IO3)6, which reveals highly anisotropic compressibility and a bulk modulus of 30.4(7) GPa.
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