A gateway towards non-collinear spin processing using three-atom magnets with strong substrate coupling

J Hermenau,M Steinbrecher,K T Ton,J Wiebe,S Lounis,A Sonntag,Chr Hübner,S Blügel,B Baxevanis,M Dos Santos Dias,R Wiesendanger,J Ibañez-Azpiroz,A A Khajetoorians

doi:10.1038/s41467-017-00506-7

J Hermenau, M Steinbrecher + Show 11 more

Open Access

https://doi.org/10.1038/s41467-017-00506-7

Copy DOI

Abstract

A cluster of a few magnetic atoms on the surface of a nonmagnetic substrate is one suitable realization of a bit for spin-based information technology. The prevalent approach to achieve magnetic stability is decoupling the cluster spin from substrate conduction electrons in order to suppress destabilizing spin-flips. However, this route entails less flexibility in tailoring the coupling between the bits needed for spin-processing. Here, we use a spin-resolved scanning tunneling microscope to write, read, and store spin information for hours in clusters of three atoms strongly coupled to a substrate featuring a cloud of non-collinearly polarized host atoms, a so-called non-collinear giant moment cluster. The giant moment cluster can be driven into a Kondo screened state by simply moving one of its atoms to a different site. Using the exceptional atomic tunability of the non-collinear substrate mediated Dzyaloshinskii–Moriya interaction, we propose a logical scheme for a four-state memory.

Highlights

A cluster of a few magnetic atoms on the surface of a nonmagnetic substrate is one suitable realization of a bit for spin-based information technology
It is, a formidable task to realize an array of few atoms with a long spin-energy relaxation time useable for information storage, which at the same time, is sufficiently coupled to substrate conduction electrons in order enable strong RKKY coupling to the array
Before we proceed with the detailed experimental investigation of these excitations, we describe spin-polarized density functional theory (DFT) calculations within the Korringa-Kohn-Rostoker Green function (KKRGF) method (Fig. 2, see Methods, Supplementary Note 2 and Supplementary Fig. 2)

Summary

Introduction

A cluster of a few magnetic atoms on the surface of a nonmagnetic substrate is one suitable realization of a bit for spin-based information technology. The prevalent approach to achieve magnetic stability is decoupling the cluster spin from substrate conduction electrons in order to suppress destabilizing spin-flips This route entails less flexibility in tailoring the coupling between the bits needed for spin-processing. With respect to information storage and processing applications, the main open questions are, whether the MAE of such a non-collinear GM system can be tuned such that Kondo screening[30] and quantum tunneling processes[13] are avoided and the system is driven to support stable spin states as in a classical magnet[31]

Methods

Results

Conclusion