High Frequency Response of Volatile Memristors

TL;DR

This paper provides an analytical framework for understanding the high-frequency electrical response of NbO2-Mott volatile memristors, revealing multiple oscillatory behaviors and linear resistor-like operation during high-frequency signals.

Contribution

It introduces analytical equations describing the high-frequency response and temperature dynamics of NbO2-Mott memristors, applicable to a broad class of volatile electrothermal switches.

Findings

Up to three steady-state oscillatory behaviors identified.

Device temperature oscillates minimally at high frequency.

Devices behave as linear resistors during each cycle.

Abstract

In this theoretical study, we focus on the high-frequency response of the electrothermal NbO2-Mott threshold switch, a real-world electronic device, which has been proved to be relevant in several applications and is classified as a volatile memristor. Memristors of this kind, have been shown to exhibit distinctive non-linear behaviors crucial for cutting-edge neuromorphic circuits. In accordance with well-established models for these devices, their resistances depend on their body temperatures, which evolve over time following Newton's Law of Cooling. Here, we demonstrate that HP's NbO2-Mott memristor can manifest up to three distinct steady-state oscillatory behaviors under a suitable high-frequency periodic voltage input, showcasing increased versatility despite its volatile nature. Additionally, when subjected to a high-frequency periodic voltage signal, the device body temperature oscillates with a negligible peak-to-peak amplitude. Since, the temperature remains almost constant over an input cycle, the devices under study behave as linear resistors during each input cycle. Based on these insights, this paper presents analytical equations characterizing the response of the NbO2-Mott memristor to high-frequency voltage inputs, demarcating regions in the state space where distinct initial conditions lead to various asymptotic oscillatory behaviors. Importantly, the mathematical methods introduced in this manuscript are applicable to any volatile electrothermal resistive switch. Additionally, this paper presents analytical equations that accurately reproduce the temperature time-waveform of the studied device during both its transient and steady-state phases when subjected to a zero-mean sinusoidal voltage input oscillating in the high-frequency limit.