Renormalization Group Seminar
and Condensed Matter Theory Seminar
April 19, 2005, 12:00, Large Seminar Room of the ITP
Carsten Honerkamp
(Max Planck Institute for Solid State Research, Stuttgart)
Charge instabilities at the metamagnetic transition
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 Sr_3 Ru_2 O_7
(Grigera et al., Science 306,1154 (2004)). As an alternative we discuss
the possibility of charge inhomogeneity on the nano scale. This extends
the analogy of the metamagnetic transition to a liquid-gas transition.
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