Flexoelectric tunnel junctions based on centrosymmetric dielectric monolayer

Abstract

Polar structures in materials provide a new pathway for controlling electron transfer in nanodevices, but are restricted to a limited number of ferroelectric materials. Here, we circumvent these limitations by developing flexoelectric tunnel junctions (FleTJs) based on centrosymmetric dielectric monolayers. In the prototype device, the flexoelectric effect induces strong electrostatic polarization fields in 1-nm-thick CrOCl monolayer barriers, which effectively modulate the band alignment of the junction, ultimately yeilding switchable conductance states with high tunnelling electroresistance (TER) up to 4 × 102. More importantly, the resistance state can be switched at a loading force as low as 253 nN, preserving the morphology of the barrier layer and ensuring excellent endurance performance for memory applications. This work establishes a versatile mechanical approach for manipulating tunnel currents at the atomic scale, advancing fundamental insights into nanoscale flexoelectricity and expanding the potential of layered dielectrics for next-generation electronics. The prototype flexoelectric tunnel junction comprises a centrosymmetric CrOCl monolayer sandwiched between a conductive tip and a metal substrate. Tip-induced flexoelectricity modulates the tunneling barrier profile, enabling repeatable switching of the I-V curve between low-resistance and high-resistance states under ultralow tip forces. This approach circumvents the strict barrier material requirements of traditional ferroelectric tunnel junctions and offers a purely mechanical method for achieving switchable conductance states at the nanoscale with low technological complexity. Graphical abstract: [Figure not available: see fulltext.]