Hybridization-driven gap in UBiNi; A Bi NMR/NQR study

Baek, S.-H.*; Curro, N. J.*; Klimczuk, T.*; 酒井 宏典; Bauer, E. D.*; Ronning, F.*; Thompson, J. D.*

Physical Review B, 79(19), p.195120_1 - 195120_4, 2009/05

https://doi.org/10.1103/PhysRevB.79.195120

We report Bi nuclear-magnetic-resonance and nuclear-quadrupole-resonance measurements on a single crystal of the Kondo insulator UBiNi. The Bi nuclear-spin-lattice relaxation rate () shows activated behavior and is well fit by a spin gap of 220 K. The Bi Knight shift () exhibits a strong temperature dependence arising from electrons, in which is negative at high temperatures and increases as the temperature is lowered. Below 50 K, shows a broad maximum and decreases slightly upon further cooling. Our data provide insight into the evolution of the hyperfine fields in a fully gapped Kondo insulator based on electron hybridization.