An orbital-selective spin liquid in a frustratedheavy fermion spinel LiV_2O_4

摘要

The pronounced enhancement of the effective mass is the primary phenomenon associatedwith strongly correlated electrons. In the presence of local moments, the large effective mass isthought to arise from Kondo coupling, the interaction between itinerant and localized electrons.However, in d electron systems, the origin is not clear because of the competing Hund’s rulecoupling. Here we experimentally address the microscopic origin for the heaviest d fermion ina vanadium spinel LiV_2O_4 having geometrical frustration. utilizing orbital-selective 51V nmR, we elucidate the orbital-dependent local moment that exhibits no long-range magnetic orderdespite persistent antiferromagnetic correlations. A frustrated spin liquid, Hund-coupled toitinerant electrons, has a crucial role in forming heavy fermions with large residual entropy. ourmethod is important for the microscopic observation of the orbital-selective localization in awide range of materials including iron pnictides, cobaltates, manganites and ruthnates.