Magnetic topological insulators (TI) provide an important material platform to explore quantum phenomena such as quantized anomalous Hall effect and Majorana modes, etc. Their successful material realization is thus essential for our fundamental understanding and potential technical revolutions. By realizing a bulk van der Waals material MnBi₄Te₇ with alternating septuple [MnBi₂Te₄] and quintuple [Bi₂Te₃] layers, we show that it is ferromagnetic in plane but antiferromagnetic along the c axis with an out-of-plane saturation field of ~0.22 T at 2 K. Our angle-resolved photoemission spectroscopy measurements and first-principles calculations further demonstrate that MnBi₄Te₇ is a Z₂ antiferromagnetic TI with two types of surface states associated with the [MnBi₂Te₄] or [Bi₂Te₃] termination, respectively. Additionally, its superlattice nature may make various heterostructures of [MnBi₂Te₄] and [Bi₂Te₃] layers possible by exfoliation. Therefore, the low saturation field and the superlattice nature of MnBi₄Te₇ make it an ideal system to investigate rich emergent phenomena.

Tetragonal CuMnAs is a room temperature antiferromagnet with an electrically reorientable Néel vector and a Dirac semimetal candidate. Direct measurements of the electronic structure of single-crystalline thin films of tetragonal CuMnAs using angle-resolved photoemission spectroscopy (ARPES) are reported, including Fermi surfaces (FS) and energy-wavevector dispersions. After correcting for a chemical potential shift of ≈− 390 meV (hole doping), there is excellent agreement of FS, orbital character of bands, and Fermi velocities between the experiment and density functional theory calculations. In addition, 2×1 surface reconstructions are found in the low energy electron diffraction (LEED) and ARPES. This work underscores the need to control the chemical potential in tetragonal CuMnAs to enable the exploration and exploitation of the Dirac fermions with tunable masses, which are predicted to be above the chemical potential in the present samples.