Magnetic topological systems based on MnBi2Te4 have recently attracted significant attention due to their rich interplay between magnetism and topological electronic states. In this work, using density functional theory (DFT), we investigate topological phase transitions (TPTs) in Mn1−xGexBi2Te4 compounds with both ferromagnetic (FM) and antiferromagnetic (AFM) ordering under variations of spin–orbit coupling (SOC) strength and uniaxial strain along the c axis. We show that the emergence of a Weyl semimetal (WSM) phase requires the crossing of bands with opposite sz spin projections along the ΓZ direction. Modulation of SOC and strain can annihilate Weyl points via spin-selective hybridization, driving transitions into trivial or non-trivial phases. Furthermore, we demonstrate that a local asymmetry in Mn/Ge substitution – particularly at 37.5% Ge concentration (Mn0.625Ge0.375Bi2Te4) – can locally frustrate the AFM alignment between adjacent Mn layers and induce a WSM state, even in globally AFM systems, without external remagnetization. To optimize Weyl point separation and enhance the anomalous Hall effect (AHE), we propose partial substitution of Mn by Fe and Te by Se.
Original languageEnglish
Article number113042
JournalJournal of Physics and Chemistry of Solids
Volume208
Issue number1
Early online date29 Jul 2025
DOIs
StateE-pub ahead of print - 29 Jul 2025

    Research areas

  • Magnetic topological insulators, Spin–orbit coupling, Topological phase transition, Uniaxial strain, Weyl semimetal

ID: 140862027