Fermi surface properties of YbCuSi

Matsuda, Tatsuma; Dung, N. D.*; Haga, Yoshinori   ; Ikeda, Shugo*; Yamamoto, Etsuji  ; Ishikura, Tatsuro*; Endo, Toyoaki*; Takeuchi, Tetsuya*; Settai, Rikio*; Onuki, Yoshichika

We succeeded in growing high-quality single crystals of a heavy electron compound YbCuSi. The electronic specific heat coefficient is determined to be 150 mJ/Kmol, which is consistent with the value of the electrical resistivity from Kadowaki-Woods relation. We succeeded in observing the de Haas-van Alphen (dHvA) oscillations. The dHvA frequencies and large cyclotron effective masses in YbCuSi are highly different from those in a non-4 reference compound YCuSi. From these dHvA results, the heavy electron state of YbCuSi is characterized by the large contribution of 4-electrons to the volume of the Fermi surface and also to the strong enhancement of effective mass caused by the spin fluctuations.