Evolution of band topology with antisite defects in the Sb-doped MnBi₄Te₇

  Magnetic topological materials attract worldwide attention because the interplay between band topology and magnetism may lead to novel topological quantum phenomena, such as quantum anomalous Hall effect and quantized magnetoelectric effect. Here we propose a tunable magnetic and topological state in Sb doping a newly discovered intrinsic antiferromagnetic (AFM) topological insulator (TI) MnBi₄Te₇. Our first-principles calculation shows that the topological ground state transfer from AFM TI to ferromagnetic axion insulator in the low doping region, and then exhibit a type-I ferrimagnetic Weyl semimetal that resulted from strong antisite disorder in the high doping region. Our calculation demonstrates that the doping series provides a fruitful platform with continuously tunable magnetism and topology for investigating emergent phenomena.