High-order anisotropic magnetoresistance in two-dimensional magnetic monolayers: First-principles study based on Fe3GeTe2 and CrTe2

Anisotropic magnetoresistance (AMR) is a well-known magnetoelectric coupling phenomenon, commonly exhibiting twofold symmetry with respect to the angle of the magnetization relative to the current. In this study, we reveal the existence of high-order AMRs in two-dimensional (2D) magnetic monolayers. Based on density functional theory (DFT) calculations of Fe3GeTe2 and CrTe2 monolayers, we find that different energy bands contribute uniquely to AMR behavior. The high-order AMR is attributed to strong spin mixing at band crossing points, which induces significant Berry curvature. This curvature also contributes to the AMR for electrons with dominant spin-up or spin-down polarization characteristics. However, for electrons exhibiting strong spin mixing, the Berry curvature effect becomes nontrivial, resulting in high-order AMR. Our findings provide an effective approach to identifying and optimizing materials with high-order AMR, which is critical for designing high-performance spintronic devices.