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Quantized conductance coincides with state instability and excess noise in tantalum oxide memristors
journal contributionposted on 2016-04-25, 09:40 authored by Wei Yi, Sergey SavelievSergey Saveliev, Gilberto Medeiros-Ribeiro, Feng Miao, M.-X. Zhang, J. Joshua Yang, A.M. Bratkovsky, R.S. Williams
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.
Published inNature Communications
CitationYI, W. ...et al., 2016. Quantized conductance coincides with state instability and excess noise in tantalum oxide memristors. Nature Communications, 7: 11142.
PublisherNature Publishing Group
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Publisher statementThis work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/
NotesThis is an Open Access Article. It is published by Nature Publishing under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0