Experimental Realization of Degenerate Fermi Gases of ^87Sr Atoms with 10 or Two Spin Components

We report the experimental realization of quantum degenerate Fermi gases of ^87Sr atoms under controlled 10- and dual-nuclear-spin configurations. Based on laser cooling and evaporative cooling, we achieve an ultracold Fermi gas of 10^5 atoms equally distributed over 10 spin states, with a temperature of T/T_\rm F=0.21. We further prepare a dual-spin gas by optically pumping atoms to the m_\rm F=9/2 and m_\rm F=7/2 states and observe a slightly lower T/T_\rm F than that for a 10-spin gas under the same trapping condition, showing efficient evaporative cooling under a decreasing number \cal N of spin states (\cal N\geqslant 2) despite the increasing importance of Pauli exclusion. Given that rethermalization becomes less efficient with \cal N approaching unity, we evaporatively cool an almost polarized gas to 130 nK. The simple and efficient preparation of ultracold Fermi gases of ^87Sr with tunable spin configurations provides a first step towards engineering topological quantum systems.