muSR studies on the trimer-based quantum spin liquid candidates Ba4NbM3O12

The recently discovered hexagonal perovskite Ba4NbM3O12 provides a new platform to investigate a quantum spin liquid (QSL) state, in which the magnetic building block M3O12 form a triangular layer via the non-magnetic NbO6 octahedra in the ab-plane. One of the series compounds, Ba4NbM3O12 (M=Ir, Rh) is considered as the promising QSL candidates, evidenced by the magnetic susceptibility and heat capacity measurements. In addition, it is revealed that the substitution of the M-site provides a pathway to control the spin-orbit coupling (SOC), leading to the tune of the magnetic ground state. Therefore, Ba4NbM3O12 (M=Ir, Rh) is an ideal system to investigate QSL physics as well as the effects of the SOC on the trimer-based triangular lattice, deserving in-depth studies to unveil the nature of the ground state and low-energy spin dynamics.