Ultra spin liquid in Lu(3)Cu(2)Sb(3)O(14)
We analyze recent measurements of C⁄T , speciﬁc heat C divided by temperature T , of recently observed ultra spin liquid. The measurements are carried out in magnetic ﬁelds on the triangular lattice compound Lu3Cu2Sb3O14. We show that the obtained heat capacity Cmag formed by ultra spin liquid as a function of temperature T versus magnetic ﬁeld B behaves very similar to the electronic speciﬁc heat Celof the HF metal YbRh2Si2 and the quantum magnet ZnCu3(OH)6Cl2. We demonstrate that the eﬀective mass of spinon M* ∝ Cmag/T exhibits the universal scaling coinciding with scaling observed in heavy fermion (HF) metals and in ZnCu3(OH)6Cl2. Based on these observations we conclude that a strongly correlated spin liquid determines the thermodynamic properties of the ultra spin liquid of Lu3Cu2Sb3O14.