Quantized conductance coincides with state instability and excess noise in tantalum oxide memristors Academic Article uri icon

abstract

  • 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 GQ=2e(2)/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.

altmetric score

  • 16

author list (cited authors)

  • Yi, W., Savel'ev, S. E., Medeiros-Ribeiro, G., Miao, F., Zhang, M., Yang, J. J., Bratkovsky, A. M., & Williams, R. S.

citation count

  • 57

publication date

  • April 2016