Quantum degenerate fermi gases of ytterbium atoms

We performed evaporative cooling for dilute gases of ytterbium (Yb) isotopes in a crossed optical dipole trap and successfully cooled two fermionic and two bosonic species down to quantum degenerate regime, following the previous realization of Bose-Einstein condensation (BEC) in Yb-174. The elastic collision rate of fermionic Yb-173 atoms with 6 spin components was found to be large enough to carry out efficient evaporation, which enables us to cool the atoms down to 0.6 T-F, where TF is the Fermi temperature. In this regime, a plunge of evaporation efficiency was observed as an effect of the Fermi degeneracy. The other fermionic isotope Yb-171 was cooled down to the temperature below TF by sympathetic cooling with bosonic Yb-174 atoms. The sympathetic cooling technique has also been applied to (YbYb)-Yb-174-Yb-176 Bose- Bose mixture. We have observed almost pure BEC of 174Yb and the bimodal distribution of Yb-176, showing the formation of BEC-BEC mixture. Moreover, we performed evaporative cooling of Yb-170 atoms and realized the BEC.