Characteristic Timescales of the Local Moment Dynamics in Hund's-metals

Abstract

We study the characteristic time scales of the fluctuating local moments in Hund's metal systems for different degrees of correlation. By analyzing the dynamical spin susceptibility in the real-time domain via the fluctuation-dissipation theorem, we determine the time scales controlling oscillation and damping of on-site fluctuations - a crucial factor for the detection of local moments with different experimental probes. We apply this procedure to realistic many-body calculations of different families of iron-pnictides and chalcogenides, explaining the material-specific trend in the discrepancies reported between experimental and theoretical estimates of the magnetic moments.