Nanoskyrmion engineering with $sp$-electron materials: Sn monolayer on SiC(0001) surface

TL;DR

This paper explores the unique magnetic properties of a Sn monolayer on SiC(0001), revealing nonlocal Coulomb interactions, significant ferromagnetic direct exchange, and the formation of nanoskyrmions driven by strong spin-orbit coupling.

Contribution

It demonstrates the importance of nonlocal direct exchange and spin-orbit effects in $sp$-electron materials, challenging conventional models and proposing a new mechanism for nanoskyrmion formation.

Findings

Presence of strong ferromagnetic direct exchange in Sn/SiC(0001)

Dominance of Dzyaloshinskii-Moriya interaction due to spin-orbit coupling

Potential for nanoskyrmion formation at realistic conditions

Abstract

Materials with $sp$-magnetism demonstrate strongly nonlocal Coulomb interactions, which opens a way to probe correlations in the regimes not achievable in transition metal compounds. By the example of Sn monolayer on SiC(0001) surface, we show that such systems exhibit unusual but intriguing magnetic properties at the nanoscale. Physically, this is attributed to the presence of a significant ferromagnetic coupling, the so-called direct exchange, which fully compensates ubiquitous antiferromagnetic interactions of the superexchange origin. Having a nonlocal nature, the direct exchange was previously ignored because it cannot be captured within the conventional density functional methods and significantly challenges ground state models earlier proposed for Sn/SiC(0001). Furthermore, heavy adatoms induce strong spin-orbit coupling, which leads to a highly anisotropic form of the spin Hamiltonian, in which the Dzyaloshinskii-Moriya interaction is dominant. The latter is suggested to be responsible for the formation of a nanoskyrmion state at realistic magnetic fields and temperatures.