Dresden 2026 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
FM: Fachverband Funktionsmaterialien
FM 18: German-French Focus Session: (Anti)ferroic states – ferroelectrics, ferroelastics and antiferroelectrics II
FM 18.6: Talk
Thursday, March 12, 2026, 12:00–12:15, BEY/0138
Investigating metallicity in layered Carpy-Galy ferroelectrics through topotactic transformation. — •Lilia Huynh1, Marko Kuvezdic1, Dongxin Zhang1, Annouk Goossens1, Luis Moreno1, Alexandre Gloter2, Lucia Iglesias1, Manuel Bibes1, and Elzbieta Gradauskaite1 — 1Laboratoire Albert Fert, Palaiseau, France — 2Laboratoire de Physique du Solide, Orsay, France
Combining seemingly incompatible properties within a single material can yield unconventional functionalities. For instance, polar metals host inversion-symmetry breaking displacements despite finite metallicity. However, they remain scarce, as conventional ferroelectricity usually relies on orbital rehybridization and gets suppressed by free charge carriers. Here, we report the epitaxial stabilization of the layered Carpy-Galy ferroelectric Sr2Nb2O7 (AnBnO3n+2, n = 4), which exhibits a geometric in-plane polarization driven by collective octahedral rotations. These films can be successfully transformed into the metallic perovskite SrNbO3 through a topotactic interfacial reduction mediated by an Al overlayer, which drives oxygen-vacancy migration and electron doping. This redox-engineering route enables fine, continuous and even reversible tuning of oxygen stoichiometry, allowing us to stabilize intermediate Sr2Nb2O7−x phases, as confirmed by XRD, XPS, STEM, and transport measurements. In contrast to bottom-up synthesis of polar metals, this top-down strategy provides fine control of metallicity in a geometric ferroelectric host and opens avenues for exploring charge- and spin-transport phenomena in polar metals.
Keywords: Layered perovskites; Ferroelectrics; Topotactic Transformation; Strontium Niobate; Polar Metals