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

Y. Itoh

doi:10.3390/magnetism6030022

paper

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

arXiv:2605.11965 · doi:10.3390/magnetism6030022

Abstract

We report on the finite temperature staggered spin susceptibility $I ¨ (Q)$ 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 $I ¨ (Q)$ 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. The absence of a Curie-Weiss temperature can serve as an identifying criterion for QCP ( $y_{0}$ = 0) in systems with weak mode-mode coupling ( $y_{1} <$ 0.1). Experimental application on the $y_{1}$ classification is shown to several itinerant layered antiferromagnetic systems through an analysis of nuclear spin-lattice relaxation rates.

6 pages, 5 figures; revised in ver.3