Strong Dzyaloshinskii-Moriya Interaction in Monolayer CrI$_3$ on Metal Substrates

TL;DR

This paper demonstrates through first-principles calculations that monolayer CrI3 on metal substrates exhibits a strong Dzyaloshinskii-Moriya interaction due to interfacial effects, opening new avenues for 2D spintronic materials.

Contribution

It reveals that substrate-induced charge transfer and chemical interactions significantly enhance DMI in 2D CrI3, a novel finding for 2D magnetic materials.

Findings

Strong DMI observed in CrI3 on Au and Cu substrates

Interfacial charge transfer enhances DMI strength

Substrate effects crucial for 2D magnet spin textures

Abstract

Dzyaloshinskii-Moriya interaction (DMI) is the primary mechanism for realizing real-space chiral spin textures, which are regarded as key components for the next-generation spintronics. However, DMI arises from a perturbation term of the spin-orbit interaction and is usually weak in pristine magnetic semiconductors. To date, large DMI and the resulting skyrmions are only realized in a few materials under stringent conditions. Using first-principles calculations, we demonstrate that significant DMI occurs between nearest-neighbor Cr atoms in two-dimensional (2D) magnetic semiconductor CrI$_3$ on Au or Cu substrates. This exceptionally strong DMI is generated by the interfacial charge transfer and weak chemical interactions between chromium halides and metal substrates, which break the spatial inversion symmetry. These findings highlight the significance of substrate effects in 2D magnets and expand the inventory of feasible materials with strong DMI.