Field induced quantum critical behavior in CeCoIn investigated by NMR

Sakai, Hironori; Brown, S. E.*; Baek, S.-H.*; Ronning, F.*; Bauer, E. D.*; Thompson, J. D.*

no journal, , 

In heavy fermion superconductor CeCoIn, non-Fermi liquid behavior has been reported to appear above kOe along the axis in the low temperature region by means of specific heat, electric resistivity, and thermal expansion measurements. Moreover, the crossover temperature from non-Fermi liquid to Fermi liquid behaviors seems to be extrapolated toward 0 K by lowering magnetic field to in the normal state. The origin of this field-induced critical behavior in the normal state of CeCoIn is investigated microscopically by means of nuclear magnetic resonance (NMR) technique.

f electron nature in the impurity state of CeLaRuSi

Matsumoto, Yuji

no journal, , 

CeRuSi is a paramagnetic heavy fermion compound with the electronic specific heat coefficient of 350 mJ / mol K. The Kondo temperature of the dilute sample with Ce concentration = 0.02 is about 1 K. We have successfully observed all the dHvA oscillations in the dilute Ce concentration samples with fields in the (001) plane. Moreover, we have observed the variation of the dHvA oscillations with temperature crossing the Kondo temperature. The present observation implies that the f electron state changes continuously from localized to itinerant with decreasing temperature from above to below the Kondo temperature.

Np nuclear relaxation rate in heavy fermion superconductor NpPdAl

Chudo, Hiroyuki; Tokunaga, Yo; Kambe, Shinsaku; Sakai, Hironori; Aoki, Dai*; Homma, Yoshiya*; Haga, Yoshinori; Matsuda, Tatsuma; Onuki, Yoshichika; Yasuoka, Hiroshi; et al.

no journal, , 

Valence band structure of YbRhSi studied by soft X-ray angle-resolved photoemission spectroscopy

Yasui, Akira; Fujimori, Shinichi; Kawasaki, Ikuto; Okane, Tetsuo; Takeda, Yukiharu; Saito, Yuji; Lapertot, G.*; Knebel, G.*; Matsuda, Tatsuma; Haga, Yoshinori; et al.

no journal, , 

In recent years, YbRhSi has been attracted much attention because it can be turned through a quantum critical point (QCP) by various small changes of control parameters. Many studies on its electronic structure have been performed for this compound to understand the nature of the QCP, but its bulk electronic structure has not been understood. Experimental observations of the valence-band structure including Yb 4 bands are needed to establish the theoretical model which describes the electronic structure of YbRhSi correctly. We have performed the soft X-ray angle-resolved photoemission spectroscopy for YbRhSi to obtain its bulk valence-band structure. Experimental valence-band structure is similar to the calculated result of LuRhSi within a local-density approximation, while the Yb 4 bands are observed near Fermi level.