Ultrafast Multilevel Switching and Synaptic Behavior in a Planar Quantum Topological Memristor

The rapid increase in data driven by analytics and Internet of Things demands innovation in both device architecture and materials to meet the growing need for fast and efficient computing. Here we report an ultrafast planar quantum topological memristor (PQTM), comprised of bismuth-telluride (Bi₂Te₃) thin film transferred onto pre-patterned electrodes. Owing to the planar architecture, the device connects both electrodes to the surface states of Bi₂Te_3, offering a platform to directly benefit from the characteristic features of topological surface states, such as low-dissipation and scattering-resistant channels essential for ultrafast- and efficient-charge transport. Pertinently, PQTM presents a forming-free bipolar-resistive switching behavior with an ultrafast-switching ∼15 ± 5 ns and low-energy consumption ∼14.5 nJ, which is a record high among the topological insulator-based memristors. Moreover, the endurance evaluation over 10³ consecutive DC-switching cycles demonstrates superior stability in both high and low resistive states, while the retention tests display an excellent longevity of ∼10⁵ s, signifying reliable non-volatile operation. Finally, PQTM reproducibility is established via comparison with 24 other devices, presenting multilevel resistive switching exhibiting both digital and analog switching modes together with long-term potentiation, depression, and persistent image-recognition performance, corroborated via 1D-convolutional layers with four LeNet models. Thus, our work emphasizes the critical role of device architecture in harnessing material properties for advanced-memory and neuromorphic applications.