Charge instabilities at the metamagnetic transition of itinerant electron systems

We investigate instabilities in the charge channel in the vicinity of (meta)magnetic transitions of itinerant electron systems. Based on a weak-coupling analysis we argue that in a one-band t-t(') Hubbard model near the van Hove filling and dominant ferromagnetic fluctuations it is difficult to account for a microscopic mechanism for a d-wave Pomeranchuk deformation of the Fermi surface. A similar deformation has been considered for the metamagnetic transition in Sr3Ru2O7. As an alternative we discuss the possibility of charge inhomogeneity on the nanoscale. This extends the analogy of the metamagnetic transition to a liquid-gas transition.