Dynamical lattice instability versus spin liquid state in a frustrated spin chain system

TL;DR

This study investigates a low-dimensional spin-1/2 compound, revealing phonon anomalies and suppressed magnetic excitations below 100K, indicating a complex interplay of spin and lattice dynamics that could lead to structural transitions.

Contribution

It provides experimental evidence of spin-lattice interactions and potential phase transitions in a frustrated spin chain system, expanding understanding of quantum spin liquids.

Findings

Phonon anomalies observed below 100K

Suppression of magnetic scattering continuum below 100K

Evidence for spin-lattice coupling and possible structural transition

Abstract

The low-dimensional s=1/2 compound (NO)[Cu(NO3)3] has recently been suggested to follow the Nersesyan-Tsvelik model of coupled spin chains. Such a system shows unbound spinon excitations and a resonating valence bond ground state due spin frustration. Our Raman scattering study demonstrates phonon anomalies as well as the suppression of a broad magnetic scattering continuum for temperatures below a characteristic temperature, T<T*=100K. We interpret these effects as evidence for a dynamical interplay of spin and lattice degrees of freedom that might lead to a further transition into a dimerized or structurally distorted phase at lower temperatures.