Possible spin liquid state in a new Jeff =1/2 triangular lattice antiferromagnet

Quantum spin liquids (QSL) represent a highly entangled state of matter that lacks long-range magnetic order, despite strong exchange interactions between its magnetic constituents and host exotic fractional excitations. Rare-earth based frustrated triangular lattice antiferromagnets wherein a subtle interplay between competing degrees of freedom provides a novel route for realizing the enigmatic QSL state with fractional excitations. The recently synthesized a structurally perfect triangular lattice K3NdTe2O9 is a promising candidate in this context. The localized Nd3+ spins show neither magnetic order nor spin-freezing state down to 60 mK suggesting a dynamic state. Thermodynamic data reveal an effective Jeff = 1/2 (Nd3+) in the Kramers doublet state and a weak antiferromagnetic interaction Jex≈ 1 K between Jeff = 1/2 moments-typical for rare-earth based frustrated magnets owing to the localized nature of 4f orbitals. The magnetic specific heat shows an anomaly ~120 mK, however, the entropy release at this temperature doesn’t correspond to that expected for Jeff = ½. This calls for a very sensitive local probe such as muon spin relaxation (µSR) that could unambiguously establish the ground state and associated magnetic excitations in the sub-Kelvin temperatures.