Is there a field-induced spin-liquid phase in $\alpha$-RuCl3?
In plain words
An in-plane magnetic field destroys the zigzag magnetic order of $\alpha$-RuCl3 near 70 to 80 kOe, and at higher field the spins line up with the field. Whether a separate spin-liquid phase exists between these regimes, or the observed features come from a smooth crossover and from structurally different pieces of the crystal, is unresolved.
Precise statement
For in-plane fields between the zigzag critical field H_c1 (about 70 to 80 kOe) and full polarization, determine whether a distinct thermodynamic phase bounded by phase transitions (in specific heat, magnetocaloric effect, magnetostriction) exists, whether its excitations form a fractionalized continuum or multi-magnon bound states, and whether the oscillatory features of $\kappa_{xx}(H)$ at $T < 1\ \mathrm{K}$ in this window mark intrinsic transitions or shifted phase boundaries of stacking inclusions. An answer is a phase diagram with identified boundaries and a classification of the intermediate state.
What would settle it
Thermodynamic measurements resolving or excluding a second transition above H_c1 on stacking-controlled crystals, combined with neutron and THz spectra fitted by a calibrated spin model.
Status in the literature
Unverified note
2025 and 2026 neutron and model studies (arXiv:2504.11458, arXiv:2601.16850) report intermediate regimes, while the $\kappa_{xx}$ oscillations of Czajka et al. (Nature Physics 2021) were attributed to field-induced transitions (Bruin et al., APL Materials 2022) and a 2026 preprint (arXiv:2605.13444) traces features beyond the zigzag regime to shifted antiferromagnetic boundaries of structural inclusions rather than nonmagnetic phases.