Bias-Driven Hot-Correlated Electrons in the Two-Dimensional Ferromagnet Fe4GeTe2

Electronic correlations can strongly influence the properties of magnetic materials, yet their role in charge transport in devices under operating conditions remains largely unexplored. Here, we show that an applied bias voltage can drive a breakdown of quasiparticle coherence in the prototypical two-dimensional ferromagnet Fe4GeTe2. Using a first-principles framework combining density functional theory, dynamical mean-field theory, and nonequilibrium Green's functions, we predict a voltage-induced transition from coherent, nearly half-metallic transport to a nonequilibrium regime dominated by strong inelastic scattering of charge carriers and collective electron-hole excitations. This emergent "hot-correlated electron" regime exhibits distinct spectral and transport signatures accessible in experiments. More generally, our results reveal how an applied bias reshapes electronic correlations in ferromagnets, modifying the current's spin-polarization and potentially impacting spintronic device performance.