  We report the production of quantum degenerate Bose-Bose mixtures of Cs and
Yb with both attractive (Cs + $^{174}$Yb) and repulsive (Cs + $^{170}$Yb)
interspecies interactions. Dual-species evaporation is performed in a
bichromatic optical dipole trap that combines light at 1070 nm and 532 nm to
enable control of the relative trap depths for Cs and Yb. Maintaining a trap
which is shallower for Yb throughout the evaporation leads to highly efficient
sympathetic cooling of Cs for both isotopic combinations at magnetic fields
close to the Efimov minimum in the Cs three-body recombination rate at around
22 G. For Cs + $^{174}$Yb, we produce quantum mixtures with typical atom
numbers of $N_\mathrm{Yb} \sim 5 \times 10^4$ and $N_\mathrm{Cs} \sim 5 \times
10^3$. We find that the attractive interspecies interaction (characterised by
the scattering length $a_\mathrm{CsYb} = -75\,a_0$) is stabilised by the
repulsive intraspecies interactions. For Cs + $^{170}$Yb, we produce quantum
mixtures with typical atom numbers of $N_\mathrm{Yb} \sim 4 \times 10^4$, and
$N_\mathrm{Cs} \sim 1 \times 10^4$. Here, the repulsive interspecies
interaction ($a_\mathrm{CsYb} = 96\,a_0$) can overwhelm the intraspecies
interactions, such that the mixture sits in a region of partial miscibility.

Quantum Gases;Atomic Physics