Quantum Conductance in Memristive Devices: Fundamentals, Developments, and Applications

Abstract

Quantum effects in novel functional materials and new device concepts represent a potential breakthrough for the development of new information processing technologies based on quantum phenomena. Among the emerging technologies, memristive elements that exhibit resistive switching, which relies on the electrochemical formation/rupture of conductive nanofilaments, exhibit quantum conductance effects at room temperature. Despite the underlying resistive switching mechanism having been exploited for the realization of next‐generation memories and neuromorphic computing architectures, the potentialities of quantum effects in memristive devices are still rather unexplored. Here, a comprehensive review on memristive quantum devices, where quantum conductance effects can be observed by coupling ionics with electronics, is presented. Fundamental electrochemical and physicochemical phenomena underlying device functionalities are introduced, together with fundamentals of electronic ballistic conduction transport in nanofilaments. Quantum conductance effects including quantum mode splitting, stability, and random telegraph noise are analyzed, reporting experimental techniques and challenges of nanoscale metrology for the characterization of memristive phenomena. Finally, potential applications and future perspectives are envisioned, discussing how memristive devices with controllable atomic‐sized conductive filaments can represent not only suitable platforms for the investigation of quantum phenomena but also promising building blocks for the realization of integrated quantum systems working in air at room temperature.

Experimental and Modeling Study of Metal–Insulator Interfaces to Control the Electronic Transport in Single Nanowire Memristive Devices

“…Interestingly, the distribution of the device conductance over cycling in the LRS normalized with respect to the fundamental quantum of conductance G 0 reported in Figure d shows that the device internal state of conductance is lower than G 0 ( G / G 0 mean value of 0.22, standard deviation of 0.03). While values close to G 0 are expected when the filament size reaches the atomic scale favoring the formation of a quantum point contact, values of G < G 0 mean that the formed filament does not allow the complete transmission of the electron wave packet. This corresponds to the tunneling regime through a subband.…”

Multi-level Cells and Quantized Conductance Characteristics of Al2O3-Based RRAM Device for Neuromorphic System

“…Pulse measurements were performed in Fig. 5 c and d to describe the quantized conductance [ 62 – 64 ]. Conductance calculated with the voltage of 0.5 V was induced by adding write pulses at 0.5 s intervals.…”

Quantized conductance behaviour observed in an atomic switch using triptycene-based polymers

“…6 Moreover, the devices showing quantized conductance have also been explored for various applications such as selectors, logic circuits, synaptic weight elements, leaky integrated-and-fire neurons, and so on. 7 For polymerbased devices, Gao et al have observed quantized conductance in a Ag/poly(3-hexylthiophene) [6,6]:-phenyl-C61-butyric acid methyl ester/ITO device under voltage sweep and pulse measurements. 8 Quantized conductance states of integer multiples of single atomic point contact and partially quantized states have been reported using graphene submicron-sized nanoplatelets embedded in a 3-hexylthiophene layer.…”