Field-Tunable Quantum Disordered Ground State in the Triangular-Lattice Antiferromagnet NaYbO2
Mitchell M. Bordelon, Eric Kenney, Chunxiao Liu, Tom Hogan, Lorenzo Posthuma, Marzieh Kavand, Yuangqi Lyu, Mark Sherwin, Nicholas P. Butch, Craig Brown, M. J. Graf, Leon Balents, Stephen D. Wilson
One of the simplest routes to pursuing magnets with strong quantum fluctuations that quench conventional order is via decorating a triangular lattice with antiferromagnetically coupled S=1/2 moments. As disorder and anisotropies inherent in materials render experimental realizations of such a lattice exceedingly rare, alternative models using spin-orbit entangled Jeff=1/2 ions have also been proposed. Native disorder in candidate materials hosting a triangular lattice of Jeff=1/2 moments has however remained an obstacle in assessing this alternate approach and motivates the identification of new, structurally perfect variants. Here we investigate such a compound in NaYbO2, which hosts an ideal triangular lattice Jeff=1/2 moments showing no signatures of conventional magnetic order down to 50 mK. Magnetic field strongly perturbs the resulting quantum disordered ground state and drives the formation interlayer exchange Our data demonstrate that the triangular lattice of Jeff=1/2 moments in NaYbO2 realizes an unconventional, quantum-disordered ground state whose critical phase boundaries are accessible under modest fields.