Quantum graph models for transport in filamentary switching

TL;DR

This paper models quantum transport in filamentary switching devices using quantum graphs to understand how atomic-scale filaments influence conductance, which is vital for advancing quantum neuromorphic hardware.

Contribution

It introduces a quantum graph approach to analyze charge transport in atomic-scale filaments, bridging the gap between classical models and quantum effects in memristive devices.

Findings

Quantum graphs effectively model atomic filament conductance.

Quantum effects significantly influence filamentary switching behavior.

The approach aids in designing quantum neuromorphic hardware.

Abstract

The formation of metallic nanofilaments bridging two electrodes across an insulator is a mechanism for resistive switching. Examples of such phenomena include atomic synapses, which constitute a distinct class of memristive devices whose behavior is closely tied to the properties of the filament. Until recently, experimental investigation of the low-temperature regime and quantum transport effects has been limited. However, with growing interest in understanding the true impacts of the filament on device conductance, comprehending quantum effects has become crucial for quantum neuromorphic hardware. We discuss quantum transport resulting from filamentary switching in a narrow region where the continuous approximation of the contact is not valid, and only a few atoms are involved. In this scenario, the filament can be represented by a graph depicting the adjacency of atoms and the overlap between atomic orbitals. Using quantum graphs, we calculate the scattering amplitude of charge carriers on this graph and explore the interplay between filamentary formation and quantum transport effects.