Feshbach resonances, molecular bound states and prospects of ultracold molecule formation in mixtures of ultracold K and Cs

Abstract

We consider the possibilities for producing ultracold mixtures of K and Cs and forming KCs molecules by magnetoassociation. We carry out coupled-channel calculations of the interspecies scattering length for $^{39}$KCs, $^{41}$KCs and $^{40}$KCs and characterize Feshbach resonances due to s-wave and d-wave bound states, with widths ranging from below 1 nG to 5 G. We also calculate the corresponding bound-state energies as a function of magnetic field. We give a general discussion of the combinations of intraspecies and interspecies scattering lengths needed to form low-temperature atomic mixtures and condensates and identify promising strategies for cooling and molecule formation for all three isotopic combinations of K and Cs.