Journal Article magnetic topological insulators 2D materials Dirac fermions Kagome‐lattice analog memory contact scaling current crowding current‐induced switching dual-gating electric fields hard ferromagnets intimate contacts low-energy memory nanocomposites negative differential resistance neuro-inspired phase-change memory nodal line metals on‐chip synthesis quantum anomalous Hall effect quantum criticality semimetals spin fluctuations spin‐orbit torque topological materials topological phase transitions topological surface states transfer length two-dimensional field-effect transistors