title: Ultracold fermionic Feshbach molecules of 23Na40K.
abstract: We report on the formation of ultracold weakly bound Feshbach molecules of 23Na40K, the first fermionic molecule that is chemically stable in its absolute ground state. The lifetime of the nearly degenerate molecular gas exceeds 100 ms in the vicinity of the Feshbach resonance. The measured dependence of the molecular binding energy on the magnetic field demonstrates the open-channel character of the molecules over a wide field range and implies significant singlet admixture. This will enable efficient transfer into the singlet vibrational ground state, resulting in a stable molecular Fermi gas with strong dipolar interactions.
authors.affiliation: MIT-Harvard Center for Ultracold Atoms, Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Cheng-Hsun
authors.initials: CH
authors.lastname: Wu
authors.forename: Jee Woo
authors.initials: JW
authors.lastname: Park
authors.forename: Peyman
authors.initials: P
authors.lastname: Ahmadi
authors.forename: Sebastian
authors.initials: S
authors.lastname: Will
authors.forename: Martin W
authors.initials: MW
authors.lastname: Zwierlein