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 Ta
₂
O
₅
or HfO
₂
. 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/Ta
₂
O
₅
/Pt devices, a larger number of quantized conductance states were obtained in the Pt/Ta/HfO
₂
/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.