Fermi Surface Reconstruction by Dynamic Magnetic Fluctuations

TL;DR

This paper shows how critical magnetic fluctuations in strongly correlated systems can alter Fermi surface topology and induce spin-charge separation, especially near quantum critical points, with implications for cuprate physics.

Contribution

It introduces a model demonstrating Fermi surface reconstruction and spin-charge separation driven by magnetic fluctuations near a quantum critical point in two-dimensional systems.

Findings

Fermi surface topology changes at a Lifshitz point within the disordered phase.

Spin-charge separation occurs near the quantum critical point.

Magnetic fluctuations influence electronic properties relevant to cuprates.

Abstract

We demonstrate that nearly critical quantum magnetic fluctuations in strongly correlated electron systems can change the Fermi surface topology and also lead to spin charge separation (SCS) in two dimensions. To demonstrate these effects we consider a small number of holes injected into the bilayer antiferromagnet. The system has a quantum critical point (QCP) which separates magnetically ordered and disordered phases. We demonstrate that in the physically interesting regime there is a magnetically driven Lifshitz point (LP) inside the magnetically disordered phase. At the LP the topology of the hole Fermi surface is changed. We also demonstrate that in this regime the hole spin and charge necessarily separate when approaching the QCP. The considered model sheds light on generic problems concerning the physics of the cuprates.