Observation of superfluidity in a strongly correlated two-dimensional Fermi gas

21 May 2021

Photo: AG Moritz

Understanding how strongly correlated two-dimensional (2D) systems can give rise to unconventional superconductivity with high critical temperatures is one of the major unsolved problems in condensed matter physics. Ultracold 2D Fermi gases have emerged as clean and controllable model systems to study the interplay of strong correlations and reduced dimensionality, but direct evidence of superfluidity in these systems has been missing.

Here, we demonstrate superfluidity in an ultracold 2D Fermi gas by moving a periodic potential through the system and observing no dissipation below a critical velocity v_c. We measure v_c as a function of interaction strength and find a maximum in the crossover regime between bosonic and fermionic superfluidity. Our measurement establishes ultracold Fermi gases as a powerful tool for studying the influence of reduced dimensionality on strongly correlated superfluids

Sobirey et al., Science 372, 844 (2021)