Electronic Structure and Magnetism of the Triple-layer Ruthenate Sr₄Ru₃O₁₀

We report electronic band structure calculations for Sr₄Ru₃O₁₀ which displays both ferromagnetic and metamagnetic behavior. The density functional calculations find the ground state to be ferromagnetic in agreement with experiment, and inclusion of Coulomb Hubbard interaction U applied to the Ru 4d states has dramatic effects on the Fermi surface, which reveal the role of Coulomb interactions and correlated many-body physics.  The minority spin bands are mainly empty with Fermi surfaces in the outer areas of the Brillouin zone with bands that disperse steeply upward.   The majority-spin bands are full or nearly full and form narrow bands near the Fermi energy around the zone center. The results are in qualitative agreement with recent angle resolved photoemission spectroscopy (ARPES) experiments [1] and show the need for a combined theoretical study and ARPES investigation with better energy resolution to reveal the nature of the narrow bands close to the Fermi-level, which is critical for understanding the exotic magnetic properties observed in this material.

[1] P. Ngabonziza, et al., Surface and kink structures in Sr4Ru3O10 revealed by synchrotron-based ARPES, Sci. Rep. 10, 21062 (2020).