Electric field-induced modification of Dzyaloshinskii-Moriya interaction in Fe/Mg0(001) with heavy metal insertions

Abstract

The effect of external electric field on the Dzyaloshinskii-Moriya interaction (DMI) in Fe/M/MgO(001) (M=Os, Ir, Pt, Au) is investigated by means of first principles full-potential linearized augmented plane wave (FLAPW)-based Density Functional Theory method. We find that, apart from the Au layer insertion, the sign of the DMI is altered by the introduction of the heavy metal, such that the magnetic chirality in Fe/M/MgO(001) is inverted from that of Fe/MgO(001). The magnitudes of DMI in the Fe/Os/MgO and Fe/Ir/MgO are enhanced by 5 - 7 times compared to that without the heavy metal insertion. The increase of the DMI can be attributed to the strength of spin-orbit coupling of the heavy metal layer, implied by the asymmetry of the orbital moments of the heavy metals within the spin spiral structures. When an external electric field is applied, no significant modification to the DMI can be observed. Our work suggests that additional heavy metal layer might be necessary for a fine control of DMI, and hence of the overall magnetic domain-related properties, by external gate voltages.