- By:
- Minelli, Arianna ; Duverger-nedellec, Elen; Perez, Olivier; Pautrat, alain; girard, adrien; Bulled, Johnathan; Mihalkovic, Marek; De boissieu, Marc; Bosak, Alexey
- Journal Name:
- IUCrJ
- Page Number:
- 441-455
- Volume:
- 13
- Issue Number:
- 4
- Publication Date:
- August 26, 2026
- View DOI Listing:
- https://doi.org/10.1107/S2052252526002836
Abstract
The m = 2 member of the monophosphate tungsten bronze family had been thought to be the only one without an electronic instability at low temperature. In this paper, we report the discovery of a charge density wave phase in this compound, with a transition temperature of 290 K and an incommensurate modulation vector q = 0.245b* + ξc*, which reaches a lock-in with a commensurate vector at 130 K. The presence of this new phase is confirmed by diffraction and resistivity measurements. Pre-transitional dynamics are investigated using diffuse and inelastic X-ray scattering, revealing a clear Kohn anomaly. We analyze both structural and electronic contributions to the phase transition, providing a comprehensive picture of the mechanism driving this newly identified instability.
