Trends in the hyperfine interactions of magnetic adatoms on thin insulating layers

Sufyan Shehada,Muayad Abusaa,Manuel Dos Santos Dias,Samir Lounis,Filipe Souza Mendes Guimarães

doi:10.1038/s41524-021-00556-y

Abstract

Nuclear spins are among the potential candidates prospected for quantum information technology. A recent breakthrough enabled to atomically resolve their interaction with the electron spin, the so-called hyperfine interaction, within individual atoms utilizing scanning tunneling microscopy (STM). Intriguingly, this was only realized for a few species put on a two-layers thick MgO. Here, we systematically quantify from first-principles the hyperfine interactions of the whole series of 3d transition adatoms deposited on various thicknesses of MgO, NaF, NaCl, h–BN, and Cu2N films. We identify the adatom-substrate complexes with the largest hyperfine interactions and unveil the main trends and exceptions. We reveal the core mechanisms at play, such as the interplay of the local bonding geometry and the chemical nature of the thin films, which trigger transitions between high- and low-spin states accompanied with subtle internal rearrangements of the magnetic electrons. By providing a general map of hyperfine interactions, our work has immediate implications in future STM investigations aiming at detecting and realizing quantum concepts hinging on nuclear spins.

Highlights

Magnetic atoms on surfaces have attracted a lot of attention due to potential applications in magnetic storage and quantum computation[1]
Experimental investigations of magnetic adatoms on thin insulating layers have mostly centered on Cu2N 3–8,20 and MgO11,12,14–18, and to a lesser extent on h–BN9,13,19, usually in connection with scanning tunneling microscopy (STM)[26]
It has been suggested that the nuclear magnetic moment instead of the electronic one could be used for application purposes

Summary

Introduction

Magnetic atoms on surfaces have attracted a lot of attention due to potential applications in magnetic storage and quantum computation[1]. The two are coupled via the hyperfine interaction[27], which provides insight into the electronic structure and chemical bonding of atoms, molecules and solids, as explored with nuclear magnetic resonance techniques. Two promising steps in this direction were recently achieved experimentally through the development of single-atom electron paramagnetic/spin resonance (EPR/ESR)[17,31,32,33,34,35,36,37,38,39,40]: The first one is the recent detection of the hyperfine interaction between the atomic nucleus and surrounding electrons for single Fe and Ti adatoms on MgO/Ag(001)[35]; The second is the control of the nuclear polarization of individual Cu adatoms on the same surface[37]. The actual mechanism underpinning the EPR/ESR experiments is still under investigation[40,41,42,43,44,45], but it is clear that a deep understanding of the hyperfine interactions in these systems is an essential piece of the puzzle

Methods

Results

Conclusion