Circuits and excitations to enable Brownian token-based computing with skyrmions

TL;DR

This paper introduces a crossing-free skyrmion-based circuit layout and a method to artificially accelerate Brownian token-based computing, enabling faster and more practical low-power magnetic computing devices.

Contribution

It presents a novel crossing-free circuit design for skyrmion-based Brownian computing and a technique to artificially enhance diffusion, significantly improving speed and feasibility.

Findings

Crossing-free skyrmion circuit layout simplifies fabrication.

Artificial diffusion mechanisms increase computation speed by orders of magnitude.

Designs are suitable for low-power, autonomous sensor applications.

Abstract

Brownian computing exploits thermal motion of discrete signal carriers (tokens) for computations. In this paper we address two major challenges that hinder competitive realizations of circuits and application of Brownian token-based computing in actual devices for instance based on magnetic skyrmions. To overcome the problem that crossings generate for the fabrication of circuits, we design a crossing-free layout for a composite half-adder module. This layout greatly simplifies experimental implementations as wire crossings are effectively avoided. Additionally, our design is shorter to speed up computations compared to conventional designs. To address the key issue of slow computation based on thermal excitations, we propose to overlay artificial diffusion induced by an external excitation mechanism. For instance, if magnetic skyrmions are used as tokens, artificially induced diffusion by spin-orbit torques or other mechanisms increases the speed of computations by several orders of magnitude. Combined with conventional Brownian computing the latter could greatly enhance the application scenarios of token-based computing for instance for low power devices such as autonomous sensors with limited power that is harvested from the environment.