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 ( μ SR ) studies on this regular (undistorted) triangular Yb sublattice based system with an effective spin Jeff = 1/2 in the temperature range 0.05–40 K. Zero-field and longitudinal-field μ SR studies confirm the absence of any long-range magnetic order state down to 0.05 K ( ∼ J / 80 ). Current μ SR results, together with the so far available bulk characterization data, suggest that NaYbS2 is an ideal candidate to identify the QSL ground state.