Stacking-Controlled Magnetic Anisotropy Switching in bilayer Janus Mn2Cl3Br3

Abstract

Bilayer Janus Mn2Cl3Br3 exhibit intriguing tunable magnetic anisotropy energy (MAE), governed by stacking configurations and halogen-specific orbital interaction. By density functional theory (DFT), we find that AA stacking in Mn2Cl3Br3 induces the MAE transition from in-plane to out-of-plane orientation, absent in bilayer Mn2Br3I3 and Mn2Cl3I3. This switching is driven by compressed Mn-Br interlayer distance that amplifies the positive contribution of MAE between px and py of Br while suppressing the pz-py contributions. In contrast, bilayer Janus Mn2Br3I3 and Mn2Cl3I3 remain in-plane MAE due to the negative contribution of the pz-py interactionof I atoms. Stacking-dependent magnetic exchange interactions further modulate MAE in bilayer Janus Mn2Cl3Br3 with AA stacking exhibiting enhanced vertical magnetic exchange anisotropy critical for MAE switching. In contrast, AB stacking preserves in-plane MAE due to suppressed magnetic interlayer coupling. The interplay of halogen orbital engineering and stacking orders offers a versatile pathway to tune the magnetic anisotropy in van der Waals magnets for designing 2D spintronic materials.