Dipolar many-body complexes and their interactions in stacked 2D heterobilayers

In the past decade, dipolar many-body complexes have been observed in 2D van der Waals heterobilayers. These complexes show compelling dipolar characteristics such as long-range and anisotropic interactions among dipoles, and their high tunability and long coherence time make them promising for applications in quantum information processing and optoelectronic devices. The presence of powerful dipole–dipole interactions among long-lived interlayer excitons can cause the system to enter unique classical and quantum phases with multiparticle correlations, which can host rich many-body physics such as dipolar liquids, dipolar crystals and superfluids. The strong binding energy of interlayer excitons in 2D heterobilayers enhances the critical temperature of these exotic phenomena. In this Review, we discuss recent work on dipolar complexes and many-body effects in transition metal dichalcogenide double layers and present potential opportunities in the field. Dipolar many-body systems provide a promising platform to study quantum phases and exotic phenomena such as dipolar liquids, dipolar solids and superfluids. This Review discusses dipolar many-body complexes and their interactions in 2D stacked transition metal dichalcogenide heterobilayers and offers insights into the unique properties of various exciton species.