| 1. |
Masanobu Shiga, Isao Maruyama, Kengo Okimura, Takurou Harada, Takuya Takahashi, Akihiro Mitsuda, Hirofumi Wada, Yuji Inagaki, Tatsuya Kawae, Evolution of lattice coherence in the intermediate-valence heavy-fermion compound EuNi2P2 studied by point contact spectroscopy, Physical Review B, 10.1103/physrevb.103.l041113, 103, 4, 2021.01, We performed a point contact spectroscopy study in an intermediate-valence heavy-fermion (HF) compound EuNi2P2. Above the Kondo temperature T-K, the differential conductance spectra show a broad peak due to the Kondo resonance at the Eu site. Below T-K, the broad peak splits into two peaks that can be reproduced by the summation of two Fano curves with the same parameters, indicating the emergence of the indirect hybridization gap in an Anderson lattice. With decreasing temperature, the separation between the two peaks increases and saturates at very low temperatures. The results reveal the evolution of the electronic structure in the HF state due to the development of the lattice coherence.. |
| 2. |
Masanobu Shiga, Kengo Okimura, Hiroki Takata, Akihiro Mitsuda, Isao Maruyama, Hirofumi Wada, Yuji Inagaki, Tatsuya Kawae, Observation of Kondo resonance in valence-ordered YbPd, Physical Review B, 10.1103/physrevb.100.245117, 100, 24, 2019.12, We performed a point-contact spectroscopy study of intermediate valence compound YbPd, in which two Yb sites are ordered with the valence values of 3+ and 2.6+. Differential conductance spectra exhibit a dip structure at around zero bias with an asymmetric background, which can be reproduced by the summation of two Kondo resonances. Fitting with the Fano equation, the Kondo temperature of the 3+ site is estimated to be similar to 30K, while that of the 2.6+ site is similar to 800K. Additionally, the dip amplitude exhibits -lnT dependence below similar to 25K and saturates at similar to 1K. These results provide direct evidence for the screening of magnetic moments at the valence ordering sites owing to the Kondo effect.. |
