Quantum anomalous Hall effect in a two-dimensional ferromagnetic NpF monolayer with high Curie temperature

Abstract

The quantum anomalous Hall (QAH) effect remains a hot topic due to its potential applications in quantum computing and low-energy electronics. Here, based on first-principles calculations and symmetry analysis, we present a new type of two-dimensional (2D) QAH insulator NpF monolayer. Our results show that the NpF monolayer favors ferromagnetic order with high Curie temperature up to 231 K. In the absence of spin–orbit coupling (SOC), the NpF monolayer is a ferromagnetic Weyl semimetal with a nodal loop near the Fermi level. When SOC with out-of-plane magnetization is taken into account, the NpF monolayer becomes a QAH insulator with C = +1, accompanied by a nontrivial band gap of 24.12 meV. When the magnetization lies in-plane and all mirror symmetries are broken, a tunable Chern-number (i.e., C = ±1) phase emerges as a function of azimuthal angles. These discoveries highlight the versatility of QAH platforms and emphasize the interplay between magnetism, topology, and spin–orbit interactions in engineering quantum phases for advanced electronic applications.