Staggered spin susceptibility at a two-dimensional antiferromagnetic quantum critical point

TL;DR

This paper investigates how zero-point quantum fluctuations influence the temperature dependence of staggered spin susceptibility at a two-dimensional antiferromagnetic quantum critical point, classifying effects based on a mode-mode coupling constant.

Contribution

It introduces a criterion based on the mode-mode coupling constant to distinguish different temperature behaviors of spin susceptibility at the quantum critical point.

Findings

Weak zero-point fluctuations lead to Curie law behavior.

Strong zero-point fluctuations cause Curie-Weiss or power law behavior.

A specific coupling constant value (0.1) separates different fluctuation regimes.

Abstract

We report on the finite temperature staggered spin susceptibility $\chi(Q)$ as a function of the mode-mode coupling constant $y_1$ in the self-consistent renormalization theory of two-dimensional antiferromagnetic spin fluctuations with zero-point quantum fluctuations just at the quantum critical point ($y_0$ = 0). We find that the value $y_1$ = 0.1 is a criterion to classify the effect of the zero-point spin fluctuations on the temperature dependence of $\chi(Q)$ into a Curie law for weak $y_1 < $ 0.1 and a Curie-Weiss type or a power law type for strong $y_1 > $ 0.1.