Strong Dzyaloshinskii-Moriya interaction in monolayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>CrI</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math> on metal substrates

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