# Observation of Feshbach resonances in an ${}^{167}$Er-${}^6$Li Fermi-Fermi mixture

## TL;DR

This study experimentally identified multiple interspecies Feshbach resonances in an ultracold mixture of erbium-167 and lithium-6 atoms, revealing broad resonances suitable for exploring novel quantum states.

## Contribution

First experimental observation of Feshbach resonances in an Er-167 and Li-6 mixture, including identification of broad resonances for future quantum state investigations.

## Key findings

- Numerous narrow and six broad Feshbach resonances detected.
- Broad resonances (>1 G) identified as promising for future research.
- Interspecies inelastic collisional properties characterized up to 800 G.

## Abstract

We present our experimental investigation of the interspecies Feshbach spectrum in a mixture of ${}^{167}$Er($F = 19/2, m_F = -19/2$)-${}^6$Li($F = 1/2, m_F = 1/2$) atoms in the microkelvin temperature regime. These temperatures are achieved by means of sympathetic cooling with ${}^{174}$Yb as a third species. Interspecies Feshbach resonances are then identified by investigation of the Er-Li inelastic collisional properties for magnetic fields up to 800 G. Numerous narrow resonances as well as six resonances with widths above 1 G could be identified. It is these broader resonances that hold much promise for interesting future investigations of, for exmample, novel superfluid states and Efimov states in large mass-imbalanced, all-fermionic two-component systems.