Figure 1

Electronic ground-state energies of ${}^6\mathrm{Li}$ and ${}^{40}\mathrm{K}$ versus magnetic field.Reuse & Permissions

Figure 2

Scheme of the atomic energy levels and transitions used to cool and trap Li and K. Also shown are the transitions used for hyperfine (hf) and Zeeman pumping of K.Reuse & Permissions

Figure 3

Schematic view of the optical trapping beam (beam 1) and the coils for the bias field and magnetic field curvature (shaded areas). Optionally, a second beam (beam 2) can be used for additional axial confinement.Reuse & Permissions

Figure 4

Illustration of the loading, transfer, and measurement timing sequence. CMOT stands for compressed MOT.Reuse & Permissions

Figure 5

Magnetic field dependence of spin relaxation. The numbers of atoms in different spin states are measured by state-selective absorption imaging after a storage time of 500 ms in the dipole trap. The solid (open) squares give the Li$|2\rangle$ ($|1\rangle$) atom number, the solid circles are $\mathrm{K}|1\rangle$. The two pronounced features that are visible at 40 and 207 G are fitted by Lorentzians to determine their positions and widths.Reuse & Permissions

Figure 6

Interpretation of the 207-G spin relaxation feature in terms of Feshbach resonances. The dots show the calculated positions of Feshbach resonances between Li$|2\rangle$ and $\mathrm{K}|2⩽j⩽10\rangle$ [33]. Also plotted is the Lorentzian fit to the Li$|2\rangle$ loss feature from Fig. 5 for comparison.Reuse & Permissions

Figure 7

Li and K atom numbers after evaporation performed at variable magnetic field. Open squares show the number of Li atoms per state; solid circles show the K atom number.Reuse & Permissions

Figure 8

Evolution of the atom numbers during the second stage of evaporation. The Li atom number per state is plotted using squares while circles represent the K atom number. Solid (open) symbols represent data from measurements using fluorescence (absorption) imaging.Reuse & Permissions

Figure 9

Temperature evolution during the last part of the evaporation. Open squares (solid circles) indicate the Li (K) temperature. Also plotted are curves that represent the evolution of the Fermi temperature for Li (dotted line) and K (dashed line).Reuse & Permissions

Figure 10

Preparation scheme of a two-component mixture near interspecies Feshbach resonances. The horizontal lines indicate four different Li-K spin channels being of particular relevance for our experiments. The numbers give the magnetic field values in Gauss. Solid (open) circles represent $s$-wave ($p$-wave) interspecies resonances. The Li$|1\rangle$ and Li$|2\rangle$ intraspecies $p$-wave resonances (not shown) are located at 160 and 215 G, respectively [39, 40], and nearly coincide with interspecies resonances. For the $s$-wave resonances, the relative widths are indicated by the size of the symbols. State transfer, indicated by vertical dashed lines, is achieved by rf transitions. After the evaporation at 1190 G, the Li$|2\rangle$ population is removed by a resonant laser pulse, as indicated by the x.Reuse & Permissions

Figure 11

Loss measurement and evaporative cooling near an interspecies Feshbach resonance. Plotted is the K atom number normalized to the background value of the loss measurement away from resonance. The open squares show a set of loss measurements holding the sample at variable magnetic field for 5 s. The solid line is a Gaussian fit to the data. The solid circles show a corresponding set of measurements where evaporation was performed by lowering the optical power to one-third of its initial value within 3 s.Reuse & Permissions

Figure 12

Scan of the Li-K Feshbach resonance at 168 G with 10-ms hold time. The $1/e$ width of the loss feature (indicated by the dotted lines) is determined by fitting a Gaussian to the experimental data and amounts to 33 mG.Reuse & Permissions

Figure 13

Molecules are associated by a magnetic field ramp, indicated by the arrow labeled $\Delta B$, across a Feshbach resonance. Transitions to higher atomic spin states are driven by rf pulses. Atoms bound in a molecule are not affected because of the binding energy $E_b$.Reuse & Permissions

Figure 14

Absorption images of LiK Feshbach molecules and unpaired atoms taken at a magnetic field of 168.19 G. The upper row shows images of molecules and atoms taken with light resonant to the K transition whereas the lower row shows images taken with light resonant to the Li transition. The left column shows molecules imaged after 0.4-ms time-of-flight (TOF) expansion and the right column unpaired atoms imaged 1 ms later.Reuse & Permissions

Figure 15

Lower bound of molecule fraction $\mathcal{F}$ in dependence of the final magnetic field value of the molecule association magnetic field ramp. Molecules are detected for fields below 168.218 G. This field corresponds to the center of the loss feature shown in Fig. 12, which is marked by the vertical solid line here. The dashed vertical lines mark the $1/e$ width of the loss feature and the horizontal dashed line marks a systematic offset.Reuse & Permissions

Figure 16

Decay of LiK molecules at 168.204 G. Plotted is the number of molecules ${\mathcal{N}}_{\mathrm{mol}}^{\mathrm{K}}$ in dependence on the hold time after the fast magnetic field ramp. The solid line is an exponential fit to the data, yielding a lifetime of 1.7 ms.Reuse & Permissions

Figure 17

Comparison of the free expansion of LiK Feshbach molecules (circles, detection of the bound K atoms; triangles, detection of the bound Li atoms) and unpaired Li atoms (open squares) at 168.196 G. Shown is the radial $1/\sqrt{e}$ width of Gaussian fits to integrated density profiles.Reuse & Permissions