Production of ⁶Li ⁸⁷Rb Feshbach molecules

Ultracold polar molecules feature long-range, anisotropic dipolar interactions, offering access to novel quantum phases and collective phenomena beyond contact-interacting gases. Microwave shielding now provides a route to engineer intermolecular interactions and suppress collisional loss, facilitating efficient cooling toward quantum degeneracy and quantitative studies of dipolar many-body physics. Here we report on the progress towards producing a degenerate Fermi gas of ultracold ⁶Li⁸⁷Rb polar molecules. Starting from a dual-species magneto-optical trap with high loading rates for both species, we transfer the atoms into a crossed optical dipole trap and perform simultaneous evaporative cooling, reaching a quasi-degenerate Li-Rb mixture. We create ⁶Li⁸⁷Rb Feshbach molecules by ramping the magnetic field downward across the interspecies Feshbach resonance near 1067 Gauss. We have observed the association-dissociation process of molecules and detected more than 2×10³ Feshbach molecules in the trap, providing a good starting point for further optimization and studies. These results establish a route to detailed spectroscopy of LiRb Feshbach molecules and constitute a key step toward producing rovibrational-ground-state molecules via stimulated Raman adiabatic passage.