Nature Communications volume 13, Article number: 4609 (2022 ) Cite this article
Mott threshold switching, which is observed in quantum materials featuring an electrically fired insulator-to-metal transition, calls for delicate control of the percolative dynamics of electrically switchable domains on a nanoscale. Here, we demonstrate that embedded metallic nanoparticles (NP) dramatically promote metastability of switchable metallic domains in single-crystal-like VO2 Mott switches. Using a model system of Pt-NP-VO2 single-crystal-like films, interestingly, the embedded Pt NPs provide 33.3 times longer ‘memory’ of previous threshold metallic conduction by serving as pre-formed ‘stepping-stones’ in the switchable VO2 matrix by consecutive electical pulse measurement; persistent memory of previous firing during the application of sub-threshold pulses was achieved on a six orders of magnitude longer timescale than the single-pulse recovery time of the insulating resistance in Pt-NP-VO2 Mott switches. This discovery offers a fundamental strategy to exploit the geometric evolution of switchable domains in electrically fired transition and potential applications for non-Boolean computing using quantum materials.
Quantum materials featuring an abrupt metal-insulator transition have fascinated researchers for their variety of potential applications in future electronics1,2,3,4,5,6,7,8,9,10. Due to the extreme sensitivity of the electronic phase transition between competing phases, a subtle perturbation by external stimuli can abruptly transform an existing phase into a different electronic phase, leading to steep modulation of the electrical properties7,8,9,10,11,12. A characteristic phenomenon during the first order metal-insulator transition is the appearance of phase separation with metallic and insulating domains with inhomogeneous distributions down to a few nanometers11,13,14,15,16,17. The existence of phase separation implies that the resistance modulation occurs through a series of percolation transforming parts of the system from one phase to the other2,11,13,14,15,16,17,18,19. This percolative nature allows for an inhomogeneous transitional state where both metallic and insulating phases coexist; the dynamics of percolative domains in the intermediate state determines the macroscopic properties related to phase transition in quantum materials2,11,13,14,15,16,17,18,19.