Charge instabilities at the metamagnetic transition

TL;DR

This paper explores charge instabilities near magnetic transitions in electron systems, suggesting charge inhomogeneity as a key factor, especially in materials like Sr$_3$Ru$_2$O$_7$, and challenges the d-wave Pomeranchuk deformation explanation.

Contribution

It provides a weak coupling analysis showing the difficulty of d-wave Fermi surface deformation near van Hove filling and proposes charge inhomogeneity as an alternative mechanism.

Findings

D-wave Pomeranchuk deformation is unlikely near van Hove filling.

Charge inhomogeneity may drive the metamagnetic transition.

Analogy between metamagnetic transition and liquid-gas transition.

Abstract

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$_7$. 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.