Chern insulating phase and layer-dependent topology in a uranium-based van-der Waals antiferromagnet

Layered antiferromagnetic (AFM) materials are drawing current interest as potential platforms for spintronics applications and for realizing unconventional superconductivity. UOTe has been synthesized recently as a new van der Walls antiferromagnet with a high Neel temperature (150 K), offering the possibility of exploring the interplay of nontrivial topology of the 5f electrons in the presence of the Kondo interaction. Here we present a systematic theoretical study of the topological states of UOTe films as a function of the number of layers. The 2-layer UOTe system is found to be a 2D AFM Chern insulator that could host quantized Hall conductivity with fully-compensated spin magnetization. We show that by applying an in-plane strain or electric field normal to the surface, the itinerant nature of the U-5f electrons can be manipulated to transition the system from the non-trivial ($C = 1$) to the trivial ($C = 0$) state. Also, UOTe is found to be a Chern insulator for films with an even number of layers but an Axion insulator for an odd number of layers. Our study suggests that UOTe is an interesting AFM materials platform for investigating topological physics and developing applications.