  We consider a heteronuclear fermionic mixture on the molecular side of an
interspecies Feshbach resonance and discuss atom-dimer scattering properties in
uniform space and in the presence of an external confining potential,
restricting the system to a quasi-2D geometry. We find that there is a peculiar
atom-dimer p-wave resonance which can be tuned by changing the frequency of the
confinement. Our results have implications for the ongoing experiments on
Lithium-Potassium mixtures, where this mechanism allows for switching the
p-wave interaction between a K atom and Li-K dimer from attractive to
repulsive, and forming a weakly bound trimer with unit angular momentum. We
show that such trimers are long-lived and the atom-dimer resonance does not
enhance inelastic relaxation in the mixture, making it an outstanding candidate
for studies of p-wave resonance effects in a many-body system.
