- Physical Review Journals
All JournalsPhysics Magazine

Physical Review B

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access

Theory-guided discovery of pressure-induced transitions in the fast-ion conductor BaSnF4

Robin Turnbull1,*, Zhang YingLong2, Claudio Cazorla3,4, Akun Liang1,5, Rahman Saqib2, Miriam Peña-Alvarez6, Catalin Popescu7, Laura Pampillo8,9, and Daniel Errandonea1

  • *Contact author: robin.turnbull@uv.es
PDF

Phys. Rev. B 112, 184104 – Published 5 November, 2025

DOI: https://doi.org/10.1103/sk37-q99z

Abstract

Fast-ion conductors such as BaSnF4 are of significant interest for next-generation solid-state battery technologies due to their high ionic conductivity and chemical stability. However, the behavior of these materials under extreme conditions remains poorly understood, despite the relevance of pressure-induced modifications for tuning functional properties. In this study, we combine density functional theory (DFT) calculations with high-pressure experiments to investigate the structural evolution of BaSnF4 up to 40 GPa. DFT predicts two pressure-induced phase transitions: from the ambient-pressure tetragonal P4/nmm phase to a monoclinic P21/m-I structure at 10 GPa, and subsequently to a denser monoclinic P21/m-II phase at 32 GPa. The first transition is experimentally confirmed via angle-dispersive X-ray diffraction, Raman spectroscopy, and electrical resistivity measurements, all performed at ambient temperature. The second transition is supported by distinct changes in high-pressure Raman modes and resistivity behavior, consistent with a further structural reorganization. These findings not only clarify the high-pressure phase diagram of BaSnF4, but also shed light on the potential for pressure-tuned ionic transport in fluorostannate-based solid electrolytes.

View figure in article

Physics Subject Headings (PhySH)

Article Text

Supplemental Material

References (44)

  1. X. He, Y. Zhu, and Y. Mo, Origin of fast ion diffusion in super-ionic conductors, Nat. Commun. 8, 15893 (2017).
  2. B. M. Voronin and S. V. Volkov, Ionic conductivity of fluorite type crystals CaF2, SrF2, BaF2, and SrCl2 at high temperatures, J. Phys. Chem. Solids 62, 1349 (2001).
  3. G. Dénès, A. Muntasar, M. C. Madamba, and J. M. Parris, Tin (II)-containing fluoride ion conductors: How tin multiplies the fluoride ion conduction by up to three orders of magnitude, WIT Trans. Eng. Sci. 133, 167 (2021).
  4. X. Lian and M. Salanne, Capturing the interactions in the BaSnF4 ionic conductor: Comparison between a machine-learning potential and a polarizable force field, J. Chem. Phys. 159, 144 (2023).
  5. A. K. Sagotra and C. Cazorla, Stress-mediated enhancement of ionic conductivity in fast-ion conductors, ACS Appl. Mater. Interfaces 9, 38773 (2017).
  6. C. Cazorla and D. Errandonea, Superionicity and polymorphism in calcium fluoride at high pressure, Phys. Rev. Lett. 113, 235902 (2014).
  7. C. Cazorla and D. Errandonea, Giant mechanocaloric effects in fluorite-structured superionic materials, Nano Lett. 16, 3124 (2016).
  8. A. K. Sagotra, D. Errandonea, and C. Cazorla, Mechanocaloric effects in superionic thin films from atomistic simulations, Nat. Commun. 8, 963 (2017).
  9. L. N. Patro and K. Hariharan, Influence of synthesis methodology on the ionic transport properties of BaSnF4, Mater. Res. Bull. 46, 732 (2011).
  10. See Supplemental Material at http://link.aps.org/supplemental/10.1103/sk37-q99z for figures and tables.
  11. R. J. Angel, M. Bujak, J. Zhao, G. D. Gatta, and S. D. Jacobsen, Effective hydrostatic limits of pressure media for high-pressure crystallographic studies, J. Appl. Cryst. 40, 26 (2007).
  12. F. Fauth, I. Peral, C. Popescu, and M. Knapp, The new material science powder diffraction beamline at ALBA synchrotron, Powder Diffr. 28, S360 (2013).
  13. C. Prescher and V. B. Prakapenka, DIOPTAS: A program for reduction of two-dimensional X-ray diffraction data and data exploration, High Press. Res. 35, 223 (2015).
  14. N. Doebelin and R. Kleeberg, Profex: A graphical user interface for the Rietveld refinement program BGMN, J. Appl. Cryst. 48, 1573 (2015).
  15. G. Shen, Y. Wang, A. Dewaele, C. Wu, D. E. Fratanduono, J. Eggert, S. Klotz, K. F. Dziubek, P. Loubeyre, O. V. Fat'yanov, and P. D. Asimow, Toward an international practical pressure scale: A proposal for an IPPS ruby gauge (IPPS-Ruby2020), High Press. Res. 40, 299 (2020).
  16. Y. Akahama and H. Kawamura, Pressure calibration of diamond anvil Raman gauge to 310 GPa, J. Appl. Phys. 100, 043516 (2006).
  17. C. Cazorla and B. Boronat, Simulation and understanding of atomic and molecular quantum crystals, Rev. Mod. Phys. 89, 035003 (2017).
  18. J. P. Perdew, A. Ruzsinszky, G. I. Csonka, O. A. Vydrov, G. E. Scuseria, L. A. Constantin, X. Zhou, and K. Burke, Restoring the density-gradient expansion for exchange in solids and surfaces, Phys. Rev. Lett. 100, 136406 (2008).
  19. G. Kresse and J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 54, 11169 (1996).
  20. P. E. Blöchl, Projector augmented-wave method, Phys. Rev. B 50, 17953 (1994).
  21. A. Togo, L. Chaput, T. Tadano, and I. Tanaka, Implementation strategies in phonopy and phono3py, J. Phys.: Condens. Matter 35, 353001 (2023).
  22. J. P. Perdew, K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple, Phys. Rev. Lett. 77, 3865 (1996).
  23. A. P. Bartók and J. R. Yates, Regularized SCAN functional, J. Chem. Phys. 150, 161101 (2019).
  24. J. Schmidt, H.-C. Wang, T. F. T. Cerqueira, S. Botti, and M. A. L. Marques, A dataset of 175k stable and metastable materials calculated with the PBEsol and SCAN functionals, Sci. Data 9, 64 (2022).
  25. G. I. Csonka, J. P. Perdew, A. Ruzsinszky, P. H. T. Philipsen, S. Lebègue, J. Paier, O. A. Vydrov, and J. G. Ángyán, Assessing the performance of recent density functionals for bulk solids, Phys. Rev. B 79, 155107 (2009).
  26. F. Tran, J. Stelzl, and P. Blaha, Rungs 1 to 4 of DFT Jacob's ladder: Extensive test on the lattice constant, bulk modulus, and cohesive energy of solids, J. Chem. Phys. 144, 204120 (2016).
  27. M. M. Ahmad, Y. Yamane, and K. Yamada, Structure, ionic conduction, and giant dielectric properties of mechanochemically synthesized BaSnF4, J. Appl. Phys. 106, 074106 (2009).
  28. M. J. Cliffe and A. L. Goodwin, PASCal: A principal axis strain calculator for thermal expansion and compressibility determination, J. Appl. Cryst. 45, 1321 (2012).
  29. J. A. Lee and G. V. Raynor, The lattice spacings of binary tin-rich alloys, Proc. Phys. Soc. B 67, 737 (1954).
  30. A. Liang, R. Turnbull, C. Popescu, F. J. Manjón, E. Bandiello, P. Rodriguez-Hernandez, A. Muñoz, I. Yousef, Z. Hebboul, and D. Errandonea, Pressure-induced phase transition and increase of oxygen-iodine coordination in magnesium iodate, Phys. Rev. B 105, 054105 (2022).
  31. J. M. Leger, J. Haines, A. Atouf, O. Schulte, and S. Hull, High-pressure x-ray-and neutron-diffraction studies of BaF2: An example of a coordination number of 11 in AX2 compounds, Phys. Rev. B 52, 13247 (1995).
  32. S. Klotz, J.-C. Chervin, P. Munsch, and G. Le Marchand, Hydrostatic limits of 11 pressure transmitting media, J. Phys. D: Appl. Phys. 42, 075413 (2009).
  33. T. Thomas, SnF2-rich supercritical fluid in the Variscan tin deposit Zinnwald/Saxony, Germany, Geol. Earth Mar. Sci. 7, 1 (2025).
  34. X. Zhang, L. Li, Y. Yu, Q. Zhang, N. Sun, Z. Mao, and D. Zhang, High pressure–temperature study of MgF2, CaF2, and BaF2 by Raman spectroscopy: Phase transitions and vibrational properties of AF2 difluorides, ACS Omega 9, 23675 (2024).
  35. E. Karaca, D. Santamaria-Perez, A. Otero-de-la-Roza, R. Oliva, K. S. Rao, S. N. Achary, C. Popescu, and D. Errandonea, Pressure-induced decomposition of Bi14WO24, Results Phys. 70, 108170 (2025).
  36. G. Dénès, M. C. Madamba, and A. Muntasar, Reactivity of SnF2 with fluorite type MF2 versus M: Synthesis of high performance fluoride ion conductors, MRS Online Proc. Lib. 547, 377 (1998).
  37. D. Errandonea, A. Muñoz, P. Rodríguez-Hernández, O. Gomis, S. N. Achary, C. Popescu, S. J. Patwe, and A. K. Tyagi, High-pressure crystal structure, lattice vibrations, and band structure of BiSbO4, Inorg. Chem. 55, 4958 (2016).
  38. A. Liang, S. Rahman, P. Rodríguez-Hernández, A. Muñoz, F. J. Manjón, G. Nenert, and D. Errandonea, High-pressure Raman study of Fe(IO3)3: Soft-mode behavior driven by coordination changes of iodine atoms, J. Phys. Chem. C 124, 21329 (2020).
  39. D. Errandonea and F. J. Manjón, On the ferroelastic nature of the scheelite-to-fergusonite phase transition in orthotungstates and orthomolybdates, Mater. Res. Bull. 44, 807 (2009).
  40. C. R. Rotundu, T. Ćuk, R. L. Greene, Z. X. Shen, R. J. Hemley, and V. V. Struzhkin, High-pressure resistivity technique for quasi-hydrostatic compression experiments, Rev. Sci. Instrum. 84, 063903 (2013).
  41. K. Suzuki, M. Cadatal-Raduban, M. Kase, and S. Ono, Band gap engineering of CaxSr1−xF2 and its application as filterless vacuum ultraviolet photodetectors with controllable spectral responses, Opt. Mater. 88, 576 (2019).
  42. G. Dénès, T. Birchall, M. Sayer, and M. F. Bell, BaSnF4—A new fluoride ionic conductor with the α-PbSnF4 structure, Solid State Ionics 13, 213 (1984).
  43. B. Mercadier, C. Legein, M. Body, T. Famprikis, M. Morcrette, E. Suard, C. Masquelier, and D. Dambournet, Insights into the micro-structure-transport relationships of the fluoride-ion conductor t−BaSnF4 synthesized by spark plasma sintering, Chem. Mater. 36, 8076 (2024).
  44. S. M. Dorfman, F. Jiang, Z. Mao, A. Kubo, Y. Meng, V. B. Prakapenka, and T. S. Duffy, Phase transitions and equations of state of alkaline earth fluorides CaF2, SrF2, and BaF2 to Mbar pressures, Phys. Rev. B 81, 174121 (2010).

Outline

Information

Phys. Rev. B 112, 184104– Published 5 November, 2025
  • Received 28 March 2025
  • Revised 18 June 2025
  • Accepted 22 September 2025
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation