Surprise in the quantum world: Disorder leads to ferromagnetic topological insulator

Nanowerk   March 21, 2023 The recent realizations of the quantum anomalous Hall effect in MnBi2Te4 and MnBi4Te7 benchmark the (MnBi2Te4)(Bi2Te3)n family as a promising hotbed for further quantum anomalous Hall effect improvements. However, the quantum anomalous Hall effect realization is complicated in MnBi2Te4 and MnBi4Te7 due to the substantial antiferromagnetic coupling between the septuple layers. Although ferromagnetic state can be stabilized by interlacing the septuple layers with an increasing number n of Bi2Te3 quintuple layers the mechanisms driving the FM state and the number of necessary quintuple layers are not understood, and the surface magnetism remains obscure. An international team […]