Conductance quantization in oxide-based resistive switching devices

Oxide-based resistive switching devices have tremendous potential in next-generation nonvolatile memory and neuromorphic applications. Here, the emergence of quantized conductance is investigated in resistive switching devices based on Ta2O5 or HfO2. By applying sweeping voltages with different current compliances or using consecutive voltage pulses, quantized conductance states including integer and half integer multiples of quantum conductance (G(0)) were observed, suggesting well-controlled formation of atomic point contacts. Compared with Pt/Ta/Ta2O5/Pt devices, a larger number of quantized conductance states were obtained in the Pt/Ta/HfO2/Pt devices. Such quantized conductance states are inherently discrete and multilevel, which could be promising for applications as multilevel nonvolatile memory and artificial synapses in hardware neural networks.