LDA + slave‐boson approach to the correlated electronic structure of the metamagnetic bilayer ruthenate Sr3Ru2O7

Abstract

AbstractThe combination of the local‐density approximation (LDA) with the rotationally invariant slave‐boson theory (RISB) is used to investigate the realistic correlated electronic structure of Sr3Ru2O7. From Wannier‐downfolding the low‐energy band structure to a three‐band model for the Ru(t2g) states, the interacting problem is solved including intra‐ and inter‐orbital Hubbard terms as well as spin‐flip and pair‐hopping interactions. Therewith it is possible to obtain valuable insight into the orbital occupations, relevant local spin multiplets, and the fermiology with increasing correlation strength. Besides generic correlation‐induced band‐narrowing and ‐shifting, an intriguing quasiparticle structure close to the Fermi level is found in the neighborhood of the notorious γ2 pocket in the Brillouin zone. Along the Γ–X direction in k‐space, that structure appears very sensitive to electronic self‐energy effects. The subtle sensitivity, connected also to its manifest multi‐orbital character, may put this very low‐energy structure in context with the puzzling metamagnetic properties of the compound.