Proximate quantum spin liquid ground state in the triangular lattice antiferromagnet TmTa7O19 with non-Kramers ion

A quantum spin liquid (QSL) represents a novel quantum state of matter wherein frustration-induced quantum fluctuations preclude conventional symmetry-breaking even at T→0, enabling long-range entanglement and supporting exotic fractional excitations ideal for quantum computing [1]. The triangular lattice antiferromagnet provides a simple prototype to achieve frustration-driven quantum phenomena including QSL. In this context, we focus on a triangular lattice compound based on a non-Kramers ion. Our initial thermodynamic measurements reveal the absence of long-range magnetic order down to 0.15 K. Interestingly, the specific heat data exhibits a crossover around 2 K: below this temperature, a power-law behavior suggests the emergence of correlated magnetism, while above 2 K, an exponential behavior indicates a gap associated with crystal electric field excitations. To probe the underlying spin dynamics in detail, we propose to perform μSR measurements down to 50 mK.