Investigating possible quantum-spin-liquid state in Nb3Cl8 using Muon spin relaxation

Cluster magnets may provide new insights in searching quantum spin liquids (QSLs). The cluster magnet Nb3Cl8 consists of S=1/2 Nb trimmers, which form an emergent triangular lattice. The system shows a paramagnetic-to-non-magnetic transition at about 100 K. Recently, it has been shown that the high-temperature electronic state is an excellent single-band Mott insulator, which raises the question whether its ground state is a QSL since the insulating QSL is born as a Mott insulator. We have found that the magnetic phase can be maintained down to lowest temperature if the single crystals are ground into powders. The low temperature-specific measurements show that the magnetic system is not ordered down to 50 mK, and has a large T-linear term with C/T (T->0) ~ 0.2 J/mol K^2. These results suggest that the magnetic phase of Nd3Cl8 may host a QSL. We thus propose to study it on MuSR to confirm the QSL behaviour.