Quantum spin liquid ground state in the disorder free triangular lattice NaYbS${}_2$

Abstract

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 YbMgGaO${}_4$, which is known for considerable structural disorder due to site intermixing, NaYbS${}_2$ delafossite realizes structurally ideal triangular layers. We present detailed $\hat{I}¼$SR studies on this regular (undistorted) triangular Yb sublattice based system with effective spin $J_{\mathrm{eff}}=1/2$ in the temperature range 0.05 - 40 K. Zero-field (ZF) and longitudinal field (LF) $\hat{I}¼$SR studies confirm the absence of any long range magnetic order state down to 0.05K ($\sim J$/80). Current $\hat{I}¼$SR results together with the so far available bulk characterization data suggest that NaYbS${}_2$ is an ideal candidate to identify QSL ground state.

Submitted to PRB as Rapid communication on 18th Oct19