Growth, characterization and Chern insulator state in MnBi₂Te₄ via the chemical vapor transport method

As the first intrinsic magnetic topological insulator (MTI), Mn-Bi-Te family has been a fruitful platform to investigate the interplay of band topology and magnetism, which can lead to emergent phenomena such as the quantum anomalous Hall effect (QAHE). In this talk, I will present our study of MnBi₂Te₄ grown by the chemical-vapor-transport (CVT) method. Our result suggests that the CVT-grown MnBi₂Te₄ single crystals are marked with lower overall defects, smaller carrier concentration with a Fermi level closer to the Dirac point, and higher mobility. In particular, a 6-layer device made from the CVT-grown sample shows by far the highest mobility of 2500 cm²V/s in MnBi₂Te₄ devices with the quantized Hall conductance appearing at 1.8 K and 8 T. I then show that this method can be applied to obtain high-quality crystals of the Mn-Bi-Te natural heterostructural families. Our study provides a new route to obtain high-quality single MnBi₂Te₄ crystals that are promising to make superior devices, and to extend the existing natural heterostructural MTI family of Mn-Bi-Te.