Identification of Dirac-like spinons in the S=1/2 Kagome antiferromagnet YCu3[OD]6.5Br2.5

One of the most sought-after many-body phenomena in quantum magnets is quantum spin liquids (QSLs) as they realize a long-range entangled spin state that negates the standard symmetry-breaking paradigm. An S=1/2 Kagome Heisenberg antiferromagnet (KHA) - a two-dimensional lattice formed by corner-sharing triangles is proposed for a paradigmatic setting for achieving QSLs. We propose the inelastic neutron scattering study of the Dirac quantum spin liquid candidate YCu3(OD)6+xBr3-x (abbreviated as YCODB). YCODB shows no magnetic ordering or freezing down to 50 mK and exhibits a nearly quadratic T dependence of specific heat, reminiscent of a Dirac-like QSL. Singularly, the highly sought-after 1/9 magnetization plateau has been observed for the first time in this compound, highlighting its importance in the research of kagome physics.