Non-monotonic temperature dependence of the Hall coefficient in Hund’s metals

A non-monotonic temperature dependence of the Hall coefficient has been reported for several strongly correlated materials, e.g. Sr₂RuO₄, Sr₃Ru₂O₇, LiFeAs and FeSe [1]. One common signature of these Hund’s metals is a strong orbital selectivity of electronic correlations. On the example of Sr₂RuO₄, where the Hall coefficient exhibits two sign reversals, we show that the behavior of the Hall coefficient is directly linked to the temperature dependence of the ratio of inelastic scattering rates between the different correlated orbitals [2]. In our picture the sign reversals reflect two important crossovers in the physics of this material: (I) from a high-T incoherent to a coherent regime at low-T associated with a remarkably large ratio of scattering rates, and (II) from inelastic to impurity-dominated scattering. This qualitative picture is supported by quantitative calculations using Boltzmann transport theory in combination with dynamical mean-field theory, taking into account the effect of spin–orbit coupling.

[1] R. Perry, et al., Phys. B 284, 1469 (2000); O. Heyer, et al., PRB 84, 064512 (2011); J. P. Sun, et al., PRL 118, 147004 (2017)
[2] M. Zingl, et al., npj Quantum Materials 4, 35 (2019)