Dimensional crossover in a spin liquid to helimagnet quantum phase transition

TL;DR

This study investigates the quantum phase transition from a spin liquid to a helimagnet in Sul--Cu$_2$Cl$_4$, revealing an incommensurate chiral phase and unusual critical behavior through neutron scattering experiments.

Contribution

It provides new insights into the magnetic field-induced quantum phase transition and identifies the chiral nature of the critical point in a quasi-1D spin system.

Findings

Identification of an incommensurate chiral high-field phase.

Measurement of critical exponents $eta oughly0.235$ and $ u oughly0.34$.

Evidence of an unusual sub-critical scaling regime.

Abstract

Neutron scattering is used to study magnetic field induced ordering in the quasi-1D quantum spin-tube compound Sul--Cu$_2$Cl$_4$ that in zero field has a non-magnetic spin-liquid ground state. The experiments reveal an incommensurate chiral high-field phase stabilized by a geometric frustration of the magnetic interactions. The measured critical exponents $\beta\approx0.235$ and $\nu\approx0.34$ at $H_c\approx3.7$ T point to an unusual sub-critical scaling regime and may reflect the chiral nature of the quantum critical point.