Excitons in strain-induced one-dimensional moire potentials at transition metal dichalcogenide heterojunctions

Abstract

The possibility of confining interlayer excitons in interfacial moire patterns has recently gained attention as a strategy to form ordered arrays of zero-dimensional quantum emitters and topological superlattices in transition metal dichalcogenide heterostructures. Strain is expected to play an important role in the modulation of the moire potential landscape, tuning the array of quantum dot-like zero-dimensional traps into parallel stripes of one-dimensional quantum wires. Here, we present real-space imaging of unstrained zero-dimensional and strain-induced one-dimensional moire patterns along with photoluminescence measurements of the corresponding excitonic emission from WSe2/MoSe(2)heterobilayers. Whereas excitons in zero-dimensional moire traps display quantum emitter-like sharp photoluminescence peaks with circular polarization, the photoluminescence emission from excitons in one-dimensional moire potentials shows linear polarization and two orders of magnitude higher intensity. These results establish strain engineering as an effective method to tailor moire potentials and their optoelectronic response on demand. The combination of piezoresponse force microscopy and optical measurements reveals the influence of strain in the formation of one-dimensional moire patterns and the resulting behaviour of interlayer excitons in van der Waals heterostructures.