Engineering antiferromagnetic topological insulators in two-dimensional NaMnBi

Antiferromagnetic (AFM) topological insulators (TIs) have recently attracted extensive attention as a platform for exploring prominent physical phenomena and innovative design of topological spintronic devices. Here, we theoretically demonstrate a topological switch between the normal insulator and AFM TI in two-dimensional NaMnBi quintuple layers. Using first-principles calculations to systematically investigate the structure, stability, magnetism, and electronic properties, we show that, while the AFM ordering is robust against external strain, the band gap and topology can be effectively tuned. Based on the spin Chern number, Wannier charge centers, and gapless edge states analysis, we identify that the AFM TI phase with out-of-plane magnetization is obtained even under a compressive strain as small as 0.58%. The presented results not only expand our understandings of magnetic topological states but also put forward potential applications in topological AFM spintronics.

Automated summary

In this study, a topological switch between normal insulator and AFM TI in two-dimensional NaMnBi quintuple layers is theoretically demonstrated. Using first-principles calculations, the researchers investigated the structure, stability, magnetism, and electronic properties, showing that the band gap and topology can be effectively tuned. The results not only expand the understanding of magnetic topological states but also propose potential applications in topological AFM spintronics.