Reconfigurable Ferroelectric-Like Two-Dimensional Electron Gas at Room Temperature

Engineering ferroelectric two-dimensional electron gases (2DEGs) offers a promising route toward nonvolatile and reconfigurable electronic functionalities, yet room temperature implementations remain scarce. Here, we report a room temperature ferroelectric-like 2DEG at the SrO- ${\mathrm{NbO}}_2$ interface between (001) ${\mathrm{SrTiO}}_3$ (STO) and $K_{0.5}{\mathrm{Na}}_{0.5}{\mathrm{NbO}}_3$ (KNN) thin films. Robust ferroelectricity is confirmed by piezoforce microscopy, optical second harmonic generation, Nb- $M_{2,3}$ /Ti- $L_{2,3}$ edges x-ray linear dichroism, scanning transmission electron microscopy, and macroscopic polarization measurements. The ferroelectric polarization enables nonvolatile control of interfacial transport and the realization of reconfigurable conducting channels with arbitrary geometry at room temperature. The coupling between ferroelectric order and 2DEG conductivity arises from the extension of the polarization into the interfacial unit cells hosting the electron gas. These results establish $K_{0.5}{\mathrm{Na}}_{0.5}{\mathrm{NbO}}_3$ / ${\mathrm{SrTiO}}_3$ heterostructures as a ferroelectric-like oxide electronic platform, opening pathways for low-power, nonvolatile electronic and spin-orbitronic devices.