Hydrostatic pressure-induced magnetic and topological phase transitions in the MnBi2Te4 family of materials

The recent discovery of intrinsic magnetic topological insulator (TI) $\mathrm{Mn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4}$ has inspired enormous research interest to explore emergent physics created by the interplay of magnetism and topology. Here we systematically investigated the influence of hydrostatic pressure on structural, magnetic, and topological electronic properties of the $\mathrm{Mn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4}$ family of materials by first-principles calculations. Our results indicate that properties of these layered materials can be effectively tuned by pressure, leading to various kinds of magnetic and topological phase transitions. These include magnetic transitions from $A$-type antiferromagnetism to novel magnetic states, such as frustrated magnetism and intralayer ferromagnetism in conditions of antiferromagnetic intralayer coupling. Moreover, rich topological phase transitions can be driven by pressure in these materials, including trivial insulator to antiferromagnetic TI, type-I or type-II Weyl semimetals, or high-order TI phases. The findings call for in-depth experimental investigations of magnetic and topological physics in these intriguing material systems under high pressure.