Dynamic Scaling in the Susceptibility of the Spin-1\2 Kagome Lattice Antiferromagnet Herbertsmithite

TL;DR

This paper demonstrates a universal scaling behavior in the magnetic response of herbertsmithite, a candidate quantum spin liquid, revealing insights into its low-energy excitations and potential quantum criticality.

Contribution

It reports a novel universal scaling relation in the magnetic susceptibility of herbertsmithite, linking it to quantum critical phenomena and disorder effects.

Findings

Universal scaling of susceptibility with H/T and ω/T.

Scaling exponent α approximately 0.66.

Evidence of quantum critical or disorder-influenced behavior.

Abstract

The spin-1/2 kagome lattice antiferromagnet herbertsmithite, ZnCu$_{3}$(OH)$_{6}$Cl$_{2}$, is a candidate material for a quantum spin liquid ground state. We show that the magnetic response of this material displays an unusual scaling relation in both the bulk ac susceptibility and the low energy dynamic susceptibility as measured by inelastic neutron scattering. The quantity $\chi T^\alpha$ with $\alpha \simeq 0.66$ can be expressed as a universal function of $H/T$ or $\omega/T$. This scaling is discussed in relation to similar behavior seen in systems influenced by disorder or by the proximity to a quantum critical point.