Triangular Kondo lattice in YbV6Sn6 and its quantum critical behavior in a magnetic field

We report on the magnetization, specific heat, and electrical resistivity for a newly discovered heavy-fermion (HF) compound, YbV6Sn6, which is crystallized in a hexagonal HfFe6Ge6-type structure, highlighted by the stacking of the triangular ytterbium sublattice and kagome vanadium sublattice. Above 2 K, YbV6Sn6 shows typical HF properties due to the Kondo effect on the Kramers doublet of Yb3+ ions in the crystalline electric field. A remarkable magnetic ordering occurs at TN = 0.40 K in zero field, while a weak external field suppresses the ordering and induces non-Fermi-liquid behavior. In strong magnetic field, the compound shows a heavy Fermi-liquid state. YbV6Sn6 is represented as one of the few examples of Yb-based HF compounds hosting a triangular Kondo lattice on which a magnetic field induces quantum criticality near zero temperature.