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Title: Has a Dirac spin liquid been realized in a material?
Plain: In a Dirac spin liquid the spinons have energies growing linearly with momentum near a few points, so the neutron signal rises linearly with energy and forms cones. Candidates have been reported in kagome and triangular compounds, but confirmation in independent materials is lacking.
Precise: In candidate materials (kagome YCu3(OH)6Br2[Br_x(OH)_1-x], triangular Yb-based compounds), establish the $U(1)$ Dirac spin liquid by its signatures: a dynamic structure factor $S(q,\omega)$ with conical continua at the predicted momenta and low-energy intensity $\sim \omega$, a magnetic heat capacity $C\sim T^2$, and monopole excitations at the predicted momenta. An answer is a material in which at least two such signatures are reproduced across samples and match a parton or numerical calculation of the Dirac spin liquid on that lattice.
Settled by: Inelastic neutron scattering with resolution below 0.1 J resolving conical continua, plus heat capacity and thermal conductivity down to about 0.05 K, on crystals with characterized site disorder.
Kind: phenomenon
Answer type: identification
References: (empty)
Literature status: contested
Status note: Zeng et al. (Nature Physics 2024, arXiv:2310.11646) reported conical spinon continua in YCu3(OD)6Br2[Br_0.33(OD)_0.67]; confirmation in independent compounds is lacking.
Posed since: (empty)