119Sn NMR on the correlated semi-metal

Itinerant to relocalized transition of f electrons in the Kondo insulator CeRu4Sn6

“…0f 4 / 5 / 2 and states gradually become significant, showing a broad What is the origin of relocalization in CeRu 4 Sn 6 ? It is unlikely to be caused by the presence of low-energy CEF excitations since the fl / 2 at low temperatures, as is the f ^2 ergy gap may suppress the density of state near the E p. However, for the same reason, the "relocalization" phenomenon cannot be caused by the opening of the hybridization gap, although previous electrical transport [31] and NMR [32] measurements suggest the onset of an energy gap was about 30 state away from the E f is also relocalized state. The opening of an enstates exhibit similar temperature 4 / 5 / 2 and 4 / V / 2 of K, which was consistent with the observed "relocalization" temperature.…”

“…Resistivity measurements show that it exhibits the semimetallic character [30]. Evidence of the onset of an energy gap at about 30 K has been found in the temperature dependence of several quantities: electrical resistivity and thermal conductivity [23,31], thermopower [31], and spin-lattice-relaxation rate in nuclear-magnetic-resonance (NMR) experiments [32]. Other resistivity measurements indicated that the opening temperature of the hybridization gap is of the order of 100 K [22,24].…”

CeRu$_4$Sn$_6$: heavy fermions emerging from a Kondo-insulating state

“…Together with U 2 Ru 2 Sn, it is a rare occurrence of KI having tetragonal crystal structure (crystallographic space group I 42m). Evidence of the onset of an energy gap at about 30 K has been found in the temperature dependence of several quantities: electrical resistivity (ρ) and thermal conductivity (κ) [5,6], spin-lattice-relaxation rate (1/T 1 ) in nuclear-magnetic-resonance (NMR) experiments [10] and thermopower (S) [5].…”