Enhancing MnBi₂Te₄ Stability by Doping

MnBi₂Te₄ (MBT) is an intrinsically magnetic topological material that possesses unique properties due to the quantum Hall effect. However, the low Mn-Bi mixed antisite formation energy is detrimental to these properties as it alters the long-range magnetic ordering in the Mn layer. Therefore, it is crucial to destabilize the antisite defects in MBT while preserving the favorable electronic properties. To this end, we utilized a screening approach to understand the role of dopants in the Mn and Bi sites. We find that Sc, Y, and La dopings prefer substitutions on the Bi site and significantly increase the Mn-Bi antisite defect formation energy. We find that the contribution from the empty s and d states of Sc, Y, and La around the Fermi level is insignificant. However, at the high concentration limit, the Bi-Te octahedra are significantly modified with doping, leading to important changes in the band structure.