Confinement of long-lived interlayer excitons in WSe₂/WS₂ heterobilayers

Recently, there has been an increased focus on controllable quantum gases with long-range anisotropic interactions to simulate condensed matter problems that have so far remained intractable. Interlayer excitons (IX) in transition metal dichalcogenides (TMDs), which have a permanent electric dipole moment, have emerged as an alternative pathway to realising quantum simulations in the solid state. Here, we create ultra-long-lived IX and demonstrate they can be trapped - an important prerequisite for future investigations. We do this by depositing a heterostructure of monolayer WSe₂ and WS₂ on a pre-patterned substrate. We observe lifetimes of IX approaching 200 μs at cryogenic temperatures, an order of magnitude longer than any previous IX and three orders for any TMD IX. Power-dependent PL evidences IX-IX interactions and the ability to confine single IX at pre-defined locations. The potential to create arbitrary trapping profiles for long-lived dipolar particles evidences the capability of TMDs to provide a unique avenue for probing exotic states of matter in degenerate gases and artificial lattices.