  We report the single-crystal growth of the non-centrosymmetric paramagnet
U3Ni3Sn4 by the Bridgman method and the Fermi surface properties detected by de
Haas-van Alphen (dHvA) experiments. We have also investigated single-crystal
U3Ni3Sn4 by single-crystal X-ray diffraction, magnetization, electrical
resistivity, and heat capacity measurements. The angular dependence of the dHvA
frequencies reveals many closed Fermi surfaces, which are nearly spherical in
topology. The experimental results are in good agreement with local density
approximation (LDA) band structure calculations based on the 5f-itinerant
model. The band structure calculation predicts many Fermi surfaces, mostly with
spherical shape, derived from 12 bands crossing the Fermi energy. To our
knowledge, the splitting of Fermi surfaces due to the non-centrosymmetric
crystal in 5f-electron systems is experimentally detected for the first time.
The temperature dependence of the dHvA amplitude reveals a large cyclotron
effective mass of up to 35m0, indicating the heavy electronic state of U3Ni3Sn4
due to the proximity of the quantum critical point. From the field dependence
of the dHvA amplitude, a mean free path of conduction electrons of up to 1950A
is detected, reflecting the good quality of the grown crystal. The small
splitting energy related to the antisymmetric spin-orbit interaction is most
likely due to the large cyclotron effective mass.
