z = 3 antiferromagnetic quantum critical point : U(1) slave-fermion theory of Anderson lattice model

TL;DR

This paper identifies a z=3 antiferromagnetic quantum critical point in heavy fermion systems using a U(1) slave-fermion approach, revealing non-Fermi liquid behavior and a continuous transition from magnetic metal to Fermi liquid.

Contribution

It introduces a novel U(1) slave-fermion framework for the Anderson lattice model, demonstrating a z=3 AF QCP with distinct thermodynamic and transport properties.

Findings

Divergent Grüneisen ratio with exponent 2/3

Temperature-linear resistivity at the QCP

Divergent uniform spin susceptibility with exponent 2/3

Abstract

We find the dynamical exponent $z = 3$ antiferromagnetic (AF) quantum critical point (QCP) in the heavy fermion quantum transition beyond the standard framework of the Hertz-Moriya-Millis theory with $z = 2$. Based on the U(1) slave-fermion representation of the Anderson lattice model, we show the continuous transition from an antiferromagnetic metal to a heavy fermion Fermi liquid, where the heavy fermion phase consists of two fluids, differentiated from the slave-boson theory. Thermodynamics and transport of the $z = 3$ AF QCP are shown to be consistent with the well known non-Fermi liquid physics such as the divergent Gr\"uneisen ratio with an exponent 2/3 and temperature-linear resistivity. In particular, the uniform spin susceptibility turns out to diverge with an exponent 2/3, the hallmark of the $z = 3$ AF QCP described by deconfined bosonic spinons.