Hubbard-Kanamori model: spectral functions, negative electron compressibility, and susceptibilities

Abstract

The two-orbital Hubbard-Kanamori model is studied using the strong coupling diagram technique. This approach allows one to take into account the interactions of electrons with spin, charge, and orbital fluctuations of all ranges. It was found that, at low temperatures, the model has four regions of the negative electron compressibility, which can lead to charge inhomogeneities with the assistance of phonons. For half-filling, the phase diagram of the model contains regions of the Mott and Slater insulators, bad-metal, and states with spin-polaron peaks. These sharp peaks at the Fermi level are seen in doped states also. A finite Hund coupling leads to a large increase of antiferromagnetic spin correlations with strong suppression of charge and orbital fluctuations near half-filling. For moderate doping, all types of correlations become comparable. They peak at the antiferromagnetic wave vector except for a narrow region with an incommensurate response. Stronger doping destroys all correlations.

12 pages, 8 figures

References in corpus (5)

• Strong electronic correlations from Hund's coupling
• Magnetism and its microscopic origin in iron-based high-temperature superconductors
• Fate of the false Mott-Hubbard transition in two dimensions
• Spatially inhomogeneous phase in the two-dimensional repulsive Hubbard model
• Spectroscopic evidence for negative electronic compressibility in a quasi-three-dimensional spin-orbit correlated metal

Cited by in corpus (2)

• Two-dimensional extended Hubbard model at half-filling
• Phase separation and pairing fluctuations in oxide materials