Featuring in Advanced Science, our recent work demonstrates memristive switching effects produced by a redox-driven oxygen exchange in tunnel junctions based on NdNiO3, a strongly correlated electron system characterized by the presence of a metal-to-insulator transition (MIT). Strikingly, a strong interplay exists between the MIT and the redox mechanism, which on the one hand modifies the MIT itself, and on the other hand, radically affects the tunnel resistance switching and the resistance states’ lifetime. That results in a unique temperature behavior and endows the junctions with multiple degrees of freedom. The obtained results raise fundamental questions on the interplay between electronic correlations and the creation and mobility of oxygen vacancies in nickelates, opening a new avenue toward mimicking neuromorphic functions by exploiting the electric-field control of correlated states.

An Oxygen Vacancy Memristor Ruled by Electron Correlations
V. Humbert, R. El Hage, G. Krieger, G. Sanchez-Santolino, A. Sander, S. Collin, J. Trastoy, J. Briatico, J. Santamaria, D. Preziosi, Javier E. Villegas
Advanced Science 2201753, 1-10 (2022)

A reversible oxygen exchange at the interface between an amorphous metal (MoSi) and a strongly correlated oxide (NNO) yields strong resistive switching effects. Interestingly the metal-to-insulator transition characteristic of NNO interplays with that redox mechanism, leading to a very unique behavior