Quantum spin liquid ground state in the disorder free triangular lattice NaYbS2

Rare-earth delafossites were recently proposed as promising candidates for the realization of an effective S = 1/2 quantum spin liquid (QSL) on the triangular lattice. In contrast to the most actively studied triangular-lattice antiferromagnet YbMgGaO4, which is known for considerable structural disorder due to site intermixing, NaYbS2 delafossite realizes structurally ideal triangular layers. We present detailed muon spin rotation (mu SR) studies on this regular (undistorted) triangular Yb sublattice based system with an effective spin J(eff) = 1/2 in the temperature range 0.05-40 K. Zero-field and longitudinal-field mu SR studies confirm the absence of any long-range magnetic order state down to 0.05 K (similar to J/80). Current mu SR results, together with the so far available bulk characterization data, suggest that NaYbS2 is an ideal candidate to identify the QSL ground state.