Quantum criticality with a twist - interplay of correlations and Kohn anomalies in three dimensions

TL;DR

This paper reveals that in three-dimensional correlated electron systems, quantum critical behavior is driven by Fermi surface Kohn anomalies rather than traditional theories, using advanced many-body techniques.

Contribution

It demonstrates, using the dynamical vertex approximation, that Kohn anomalies dominate quantum criticality in the 3D Hubbard model, challenging conventional Hertz-Millis-Moriya theory.

Findings

Quantum critical behavior is driven by Kohn anomalies.

Strong correlations do not alter the dominance of Kohn anomalies.

The study advances understanding of quantum phase transitions in correlated materials.

Abstract

A general understanding of quantum phase transitions in strongly correlated materials is still lacking. By exploiting a cutting-edge quantum many-body approach, the dynamical vertex approximation, we make an important progress, determining the quantum critical properties of the antiferromagnetic transition in the fundamental model for correlated electrons, the Hubbard model in three dimensions. In particular, we demonstrate that -in contradiction to the conventional Hertz-Millis-Moriya theory- its quantum critical behavior is driven by the Kohn anomalies of the Fermi surface, even when electronic correlations become strong.