  We report on the experimental realization of ultracold $^{174}{\rm
Yb}$-$^{7}{\rm Li}$ (Boson-Boson) and $^{173}{\rm Yb}$-$^{7}{\rm Li}$
(Fermion-Boson) mixtures. They are loaded into three dimensional (3D) or one
dimensional (1D) optical lattices that are species-selectively deep for the
heavy Ytterbium (Yb) and shallow for the light bosonic Lithium (Li) component,
realizing novel mixed dimensional systems. In the 1D optical lattice the band
structure of $^{173}{\rm Yb}$ is reconstructed in the presence of $^{7}{\rm
Li}$. Spectroscopic measurements of the $^{174}{\rm Yb}$-$^{7}{\rm Li}$ mixture
in the 3D lattice give access to the $^{174}{\rm Yb}$ Mott-insulator structure.
Ground state inter-species scattering lengths are determined to be $|a_{\rm
bg}(^{174}{\rm Yb}$-$^{7}{\rm Li})|=(1.11 \pm 0.17)~{\rm nm}$ and $|a_{\rm
bg}(^{173}{\rm Yb}$-$^{7}{\rm Li})|=(1.16 \pm 0.18)~{\rm nm}$. The formation
and characterization of an ultracold $^{173}{\rm Yb}$-$^{7}{\rm Li}$ mixture is
a first step towards a possible realization of a topological $p_x + i\,p_y$
superfluid in this system.
