Magnetization-Controlled Topological Switching and Spin-Texture Coupling in a Janus Re2I3Br3 Monolayer

Abstract

A magnetization-driven multi-space topological coupling mechanism is predicted in the Janus Re2I3Br3 monolayer using effective k·p and tight-binding models. The system exhibits high-Tc (∼230 K) ferromagnetic half-metallicity and a magnetization-controlled topological switch, realizing a quantum anomalous Hall (QAH) state (C = 2) with out-of-plane magnetization and a second-order topological insulator (C = 0) with in-plane magnetization. Symmetry maps the QAH phase to integer real-space topological charges (skyrmions, Q = ±1) and the SOTI phase to half-integer charges (merons, Q = ±1/2). Structural inversion asymmetry generates a sizable Dzyaloshinskii–Moriya interaction (|D| = 0.58 meV), enabling such chiral spin textures. Domain-wall simulations with these textures produce chiral bound states (CBSs) from electronic topology. The CBS localization length ξ, scales inversely with the spin-rotation gradient γ (ξ ∝ 1/γ), which is determined by the topological charge Q. This yields the universal chain |Q|↑ → γ↓ → ξ↑, directly linking magnetic topology to electronic properties. Beyond magnetic control, electron correlation provides an additional tuning parameter. Hubbard Ueff drives a topological phase transition in the QAH state, defining its stability window. Thus, magnetization orientation and correlation strength Ueff form a dual-control strategy for engineering multi-space topological states, offering a general design principle for correlated topological spintronics.