Mechanically-Induced Resistive Switching in Ferroelectric Tunnel Junctions

Abstract

Recent advances in atomic-precision processing of oxide ferroelectrics—materials with a stable polarization that can be switched by an external electric field—have generated considerable interest due to rich physics associated with their fundamental properties and high potential for application in devices with enhanced functionality. One of the particularly promising phenomena is the tunneling electroresistance (TER) effect—polarization-dependent bistable resistance behavior of ferroelectric tunnel junctions (FTJ). Conventionally, the application of an electric field above the coercive field of the ferroelectric barrier is required to observe this phenomenon. Here, we report a mechanically induced TER effect in ultrathin ferroelectric films of BaTiO₃ facilitated by a large strain gradient induced by a tip of a scanning probe microscope (SPM). The obtained results represent a new paradigm for voltage-free control of electronic properties of nanoscale ferroelectrics and, more generally, complex oxide materials.