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

TL;DR

This study systematically analyzes hyperfine interactions of 3d transition adatoms on various thin insulating layers using first-principles calculations, revealing key trends and mechanisms relevant for quantum information applications.

Contribution

It provides a comprehensive first-principles map of hyperfine interactions across multiple adatom-substrate combinations, identifying key factors influencing these interactions.

Findings

Identified adatom-substrate complexes with the largest hyperfine interactions.

Unveiled how local bonding geometry and chemical nature influence hyperfine interactions.

Revealed transitions between high- and low-spin states affecting nuclear-electron spin coupling.

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 Cu$_2$N 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.