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

As the first intrinsic antiferromagnetic topological insulator, ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ has provided a platform to investigate the interplay of band topology and magnetism as well as the emergent phenomena arising from such an interplay. Here we report the chemical-vapor-transport (CVT) growth and characterization of ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$, as well as the observation of the field-induced quantized Hall conductance in 6-layer devices. Through comparative studies between our CVT-grown and flux-grown ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ via magnetic, transport, scanning tunneling microscopy, and angle-resolved photoemission spectroscopy measurements, we find that CVT-grown ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ is marked with higher Mn occupancy on the Mn site, slightly higher ${\mathrm{Mn}}_{\mathrm{Bi}}$ antisites, smaller carrier concentration, and a Fermi level closer to the Dirac point. Furthermore, a 6-layer device made from the CVT-grown sample shows by far the highest mobility of 2500 ${\mathrm{cm}}^{2}\phantom{\rule{0.16em}{0ex}}\mathrm{V}\phantom{\rule{0.16em}{0ex}}\mathrm{s}$ in ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ devices with the quantized Hall conductance appearing at 1.8 K and 8 T. Our study provides a route to obtain high-quality single crystals of ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ that are promising to make superior devices and realize emergent phenomena, such as the layer Hall effect and quantized anomalous Hall effect, etc.