Intrinsic Quantum Anomalous Hall Effect in Two-Dimensional Trigonal-Lattice Mn4O6 Monolayer

Abstract

The quantum anomalous Hall (QAH) effect characterized by quantized Hall conductance in the absence of external magnetic fields offers promising prospects for low-power quantum electronics. In this work, we identify a Mn4O6 monolayer as a stable two-dimensional intrinsic QAH material based on first-principles calculations and systematically investigate its magnetic and topological properties. The Mn4O6 monolayer exhibits a robust out-of-plane ferromagnetic ground state with a relatively high Curie temperature (TC) of 171 K. The Mn4O6 monolayer is a half-metal with the band crossing at the K point without spin–orbit coupling (SOC). Upon inclusion of SOC, the symmetry protection is lifted, leading to the opening of a band gap and driving the system into a QAH insulator. In addition, a three-band tight-binding model is constructed based on the first-principles results to further elucidate the topological origin of the Mn4O6 monolayer. Our work deepens the understanding of QAH and underscores its promise for next-generation electronic devices.