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.