The search for supersolidlike phases has attracted great attention in the fields of condensed matter and ultracold atom physics. Here, we experimentally demonstrate a route for realizing a superfluid stripe phase in a spin-orbit coupled Bose-Einstein condensate by employing a weak optical lattice to induce momentum-space hopping between two spin-orbit band minima. We characterize the striped ground state as a function of lattice coupling strength and spin-orbit detuning and find good agreement with mean-field simulations. We observe coherent Rabi oscillations in momentum space between two band minima and demonstrate a long lifetime of the ground state. Our work offers an exciting and stable experimental platform for exploring superfluid stripe phases and their exotic excitations, which may shed light on the properties of supersolidlike states.

• Received 4 September 2018

DOI:https://doi.org/10.1103/PhysRevA.99.051602