Ground state of the layered triangular antiferromagnet YbZnGaO4

YbMgGaO4 and YbZnGaO4 are recently discovered triangular antiferromagnets , which contain quasi-2D layers of Yb3+ ions. These ions experience strong spin orbit coupling and have an effective spin of 1/2. YbMgGaO4 has been proposed to be the first candidate system for a quantum spin liquid state with strong spin orbit coupling and experiments indicate that it indeed remains disordered down to 60 mK, while also exhibiting antiferromagnetic correlations. However, recent theoretical calculations suggest that it in fact adapts a stripe-ordered state which mimics a spin-liquid state. YbZnGaO4 is an ideal candidate to test this scenario: it is isostructural to YbMgGaO4 but the substitution of Mg2+ with Zn2+ may reduce the effect of disorder due to the closer match of ionic radii and electronic configuration with the Ga3+ ions. Muons are ideal in probing the properties of this new material.