6-Bit Storage and Statistical Evolution of Quantum Conductance in a Ta₂O₅-Based Memristor Device

We report on the evidenced conductance quantization and 6-bit memory states in the Ta 2 O 5 -based memristors. From the I – V characteristics, it is affirmed that the device exhibits stable bipolar resistive switching. During the reset process, the device shows quantization for the conductance in the multiple of integral and half-integral values of G 0 ∼ 7.74809 × 10 –5 S. X - ray photoelectron spectroscopy and conductive-atomic force microscopy confirm the conducting filament model through oxygen defects in Ta 2 O 5 -based memristor device. The existence of oxygen defect-mediated 1D conductive filaments is confirmed by determining the temperature coefficient of resistance (TCR) and is determined to be 5.28 × 10 –4 K –1 . The stability of the integral and half-integral quantized states is extracted from the relative standard deviation values (maximum RSD is 14% at 0.5 G 0 and the minimum is 0.91% at 10 G 0 ), obtained by Gaussian fitting of the conductance data. Upon varying the pulse amplitude, up to 68 (>2 6 ) memory states are evidenced, which demonstrates a 6 - bit memory. Despite the above, 36 (>2 5 ) quantized conductance ( G 0 ) states in the multiple of 0.5 G 0 are apparent from number of cycles vs. G/G 0 graph. These 32 quantum conductance and 6-bit memory states would indeed be helpful for future multibit data storage devices, neuromorphic applications, and in quantum information processing.