Quantum criticality of reconstructing Fermi surfaces in antiferromagnetic metals

TL;DR

This paper uses functional renormalization group methods to analyze a quantum critical point in two-dimensional antiferromagnetic metals, revealing strong coupling between order parameters and quasiparticles, and providing critical exponents and spectral weight variations.

Contribution

It introduces a fixed point controlling the quantum criticality involving Fermi surface reconstruction with a coupled order parameter and fermions, applicable to models studied by quantum Monte Carlo.

Findings

Critical exponents for the quantum critical point.

Spectral weight variation around the Fermi surface.

Strong coupling between order parameter and quasiparticles.

Abstract

We present a functional renormalization group analysis of a quantum critical point in two-dimensional metals involving Fermi surface reconstruction due to the onset of spin-density wave order. Its critical theory is controlled by a fixed point in which the order parameter and fermionic quasiparticles are strongly coupled and acquire spectral functions with a common dynamic critical exponent. We obtain results for critical exponents and for the variation in the quasiparticle spectral weight around the Fermi surface. Our analysis is implemented on a two-band variant of the spin-fermion model which will allow comparison with sign-problem-free quantum Monte Carlo simulations.