Diluting a triangular-lattice spin liquid: Synthesis and characterization of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>NaYb</mml:mi><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:msub><mml:mi>Lu</mml:mi><mml:mi>x</mml:mi></mml:msub><mml:msub><mml:mi mathvariant="normal">S</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> single crystals

Yb-based magnets, with a perfect triangular lattice of pseudospin-$\frac{1}{2}\phantom{\rule{4pt}{0ex}}{\mathrm{Yb}}^{3+}$ ions, have emerged as candidates for realizing quantum spin-liquid state, ${\mathrm{NaYbS}}_{2}$ being prominent example. Here, we present the solid-solution series ${\mathrm{NaYb}}_{1\ensuremath{-}x}{\mathrm{Lu}}_{x}{\mathrm{S}}_{2}$ well-defined single crystals over entire substitution range $0\ensuremath{\le}x\ensuremath{\le}1$. Chemical and structural analysis indicate statistically homogeneous replacement ${\mathrm{Yb}}^{3+}$ by ${\mathrm{Lu}}^{3+}$ ions. We magnetically characterize relatively small using electron spin resonance (ESR). Below $30\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, ESR intensity can be well described Curie-Weiss function all $x$, decreasing Weiss temperature increasing Lu content. This reduction average magnetic interaction upon is also supported magnetization measurements. Importantly, no signs or spin-glass order are detected down to $2\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ any $x$. For $x&gt;0.5$, linewidth strongly increases, indicating breakup system into disconnected clusters, expected from percolation physics. The experimental data found in good agreement $x$ results classical Monte Carlo simulations triangular-lattice Heisenberg model, amended second-neighbor interaction. Taken together, our establish family diluted liquids.