Topotactic fluorination of intermetallics as an efficient route towards quantum materials

Jean-Baptiste Vaney (1) , Baptiste Vignolle (1) , Alain Demourgues (1) , Etienne Gaudin (1) , Etienne Durand (1) , Christine Labrugère (2) , Fabio Bernardini (3) , Andrés Cano (4) , Sophie Tencé (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 PLACAMAT - Plateforme Aquitaine de Caractérisation des Matériaux
3 UniCa - Università degli Studi di Cagliari = University of Cagliari
4 NEEL - TMC - Théorie de la Matière Condensée

Intermetallics represent an important family of compounds, in which insertion of light elements (H, B, C, N) has been widely explored for decades to synthesize novel phases and promote functional materials such as permanent magnets or magnetocalorics. Fluorine insertion, however, has remained elusive so far since the strong reactivity of this atypical element, the most electronegative one, tends to produce the chemical decomposition of these systems. Here, we introduce a topochemical method to intercalate fluorine atoms into intermetallics, using perfluorocarbon reactant with covalent C-F bonds. We demonstrate the potential of this approach with the synthesis of non-stoichiometric mixed anion (Si-F) LaFeSiF x single-crystals, which are further shown to host FeSi-based superconductivity. Fluorine topochemistry on intermetallics is thus proven to be an effective route to provide functional materials where the coexistence of ionic and metallo-covalent blocks, and their interactions through inductive effects, is at the root of their functional properties.

Domaines: Matériaux

Jean-Baptiste Vaney, Baptiste Vignolle, Alain Demourgues, Etienne Gaudin, Etienne Durand, et al.. Topotactic fluorination of intermetallics as an efficient route towards quantum materials. Nature Communications, 2022, 13, pp.1462. ⟨10.1038/s41467-022-29043-8⟩. ⟨hal-03616890⟩