Staggered Spin Susceptibility at a Two-Dimensional Antiferromagnetic Quantum Critical Point

Key Points

• The aim is to understand how staggered spin susceptibility behaves in two-dimensional antiferromagnetic systems at a quantum critical point.
• Utilized self-consistent renormalization theory to analyze staggered spin susceptibility χ(Q) as a function of the mode–mode coupling constant y1.
• Classified the effects of zero-point spin fluctuations into different types based on the value of y1 (y1 < 0.1 and y1 > 0.1).
• Applied findings to experimental data regarding nuclear spin–lattice relaxation rates in several antiferromagnetic systems.
• Identified y1 = 0.1 as a criterion separating the effects of zero-point spin fluctuations.
• For weak coupling (y1 < 0.1), χ(Q) follows a Curie law, while for strong coupling (y1 > 0.1), it follows a Curie–Weiss or power law type.
• Demonstrated that the absence of Curie–Weiss temperature is a criterion for identifying quantum critical points in weakly coupled systems.