Zigzag antiferromagnetic property of two-dimensional NiPX₃ (X = S/Se) monolayers in their pristine structure and...

Transition metal phosphorous trichalcogenides TMPX₃ (TM = transition metal, X = S/Se) with a variety of spin configurations serve as excellent platforms for studying the magnetic properties of two-dimensional systems. As an antiferromagnetic semiconductor, the coexistence of ferromagnetic and antiferromagnetic couplings between the nearest neighboring metal ions of NiPX₃ remains a debatable topic. In this work, the electronic structures and magnetic properties of NiPX₃ monolayers in their pristine structure and Janus phase were systemically investigated using first-principles calculations. It was found that the NiPX₃ system possessed an indirect band gap in the zigzag antiferromagnetic ground state with a sizable Néel temperature, as estimated by Monte Carlo simulations. Electronic structures and crystal orbital Hamilton population analyses revealed that the zigzag antiferromagnetic ordering was primarily driven by superexchange interactions through p-d hybridization. Meanwhile, the coexistence of ferromagnetic and antiferromagnetic couplings was facilitated through a combination of antibonding and bonding states below the Fermi level. This work provides a new approach to explore the diverse and intriguing magnetic properties of two-dimensional materials.