Pressure-Induced Phase Transition and Band-Gap Decrease in Semiconducting Na3bi(Io3)6

41 Pages Posted: 25 Oct 2022

See all articles by Robin Turnbull

Robin Turnbull

University of Valencia

Javier González-Platas

University of La Laguna

Akun Liang

University of Valencia

Dequan Jiang

Center for High Pressure Science and Technology Advanced Research

Yonggang Wang

Center for High Pressure Science and Technology Advanced Research

Catalin Popescu

affiliation not provided to SSRN

Placida Rodriguez-Hernandez

University of La Laguna

Alfonso Munoz

University of La Laguna

Jordi Ibáñez

affiliation not provided to SSRN

Daniel Errandonea

University of Valencia

Abstract

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.

Keywords: Matter at Extreme Conditions, New materials, phase transitions, High Pressure, Synchrotron X-ray diffraction

Suggested Citation

Turnbull, Robin and González-Platas, Javier and Liang, Akun and Jiang, Dequan and Wang, Yonggang and Popescu, Catalin and Rodriguez-Hernandez, Placida and Munoz, Alfonso and Ibáñez, Jordi and Errandonea, Daniel, Pressure-Induced Phase Transition and Band-Gap Decrease in Semiconducting Na3bi(Io3)6. Available at SSRN: https://ssrn.com/abstract=4257696 or http://dx.doi.org/10.2139/ssrn.4257696

Robin Turnbull (Contact Author)

University of Valencia ( email )

Avda. de los Naranjos s/n
Valencia, E-46022
Spain

Javier González-Platas

University of La Laguna ( email )

La Laguna, Tenerife, 38071
Spain

Akun Liang

University of Valencia ( email )

Avda. de los Naranjos s/n
Valencia, E-46022
Spain

Dequan Jiang

Center for High Pressure Science and Technology Advanced Research ( email )

Shanghai
China

Yonggang Wang

Center for High Pressure Science and Technology Advanced Research ( email )

Shanghai
China

Catalin Popescu

affiliation not provided to SSRN ( email )

No Address Available

Placida Rodriguez-Hernandez

University of La Laguna ( email )

La Laguna, Tenerife, 38071
Spain

Alfonso Munoz

University of La Laguna ( email )

La Laguna, Tenerife, 38071
Spain

Jordi Ibáñez

affiliation not provided to SSRN ( email )

No Address Available

Daniel Errandonea

University of Valencia ( email )

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