Stochastic Computing Implemented by Skyrmionic Logic Devices

TL;DR

This paper demonstrates the implementation of stochastic computing using skyrmionic logic devices, including multipliers and multiplexers, with improved robustness and potential for optimized performance in advanced materials.

Contribution

It introduces skyrmionic logic devices for stochastic computing, including novel designs for AND-OR logic and multiplexers, with control mechanisms like VCMA and SOT, validated through micromagnetic simulations.

Findings

Successful simulation of 3-bit stochastic multiplier and adder.

Enhanced robustness via voltage-controlled magnetic anisotropy.

Potential for performance optimization in synthetic antiferromagnets.

Abstract

Magnetic skyrmion, topologically non-trivial spin texture, has been considered as promising information carrier in future electronic devices because of its nanoscale size, low depinning current density and high motion velocity. Despite the broad interests in skyrmion racetrack memory, researchers have been recently exploiting logic functions enabled by using the particle-like behaviors of skyrmions. These functions can be applied to unconventional computing, such as stochastic computing (SC), which treats data as probabilities and is superior to binary computing due to its simplicity of logic operation. In this work, we demonstrate SC implemented by skyrmionic logic devices. We propose a skyrmionic AND-OR logic device as a multiplier in the stochastic domain and two skyrmionic multiplexer (MUX) logic devices as stochastic adders. With the assist of voltage controlled magnetic anisotropy (VCMA), the precise control of skyrmions collision is not required in the skyrmionic AND-OR logic device, thus improving the operation robustness. In the two MUX logic devices, skyrmions can be driven by Zhang-Li torque or spin orbit torque (SOT). Particularly, we can flexibly regulate the skyrmion motion by VCMA or voltage controlled Dzyaloshinskii-Moriya Interaction (VCDMI) in the SOT case. Furthermore, 3-bit stochastic multiplier and adder are demonstrated by micromagnetic simulations. In addition, simulations in synthetic antiferromagnets (SAF) show that the performance of our skyrmionic logic gates can be optimized through advanced materials. Our work opens up perspective to implement SC using skyrmionic logic devices.