2134/21047 Wei Yi Wei Yi Sergey Saveliev Sergey Saveliev Gilberto Medeiros-Ribeiro Gilberto Medeiros-Ribeiro Feng Miao Feng Miao M.-X. Zhang M.-X. Zhang J. Joshua Yang J. Joshua Yang A.M. Bratkovsky A.M. Bratkovsky R.S. Williams R.S. Williams Quantized conductance coincides with state instability and excess noise in tantalum oxide memristors Loughborough University 2016 untagged Physical Sciences not elsewhere classified 2016-04-25 09:40:57 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/Quantized_conductance_coincides_with_state_instability_and_excess_noise_in_tantalum_oxide_memristors/9408773 Tantalum oxide memristors can switch continuously from a low-conductance semiconducting to a high-conductance metallic state. At the boundary between these two regimes are quantized conductance states, which indicate the formation of a point contact within the oxide characterized by multistable conductance fluctuations and enlarged electronic noise. Here, we observe diverse conductance-dependent noise spectra, including a transition from 1/f 2 (activated transport) to 1/f (flicker noise) as a function of the frequency f, and a large peak in the noise amplitude at the conductance quantum GQ¼2e2/h, in contrast to suppressed noise at the conductance quantum observed in other systems. We model the stochastic behaviour near the point contact regime using Molecular Dynamics–Langevin simulations and understand the observed frequency-dependent noise behaviour in terms of thermally activated atomic-scale fluctuations that make and break a quantum conductance channel. These results provide insights into switching mechanisms and guidance to device operating ranges for different applications.