Room-temperature local strain control of moiré excitons in MoS$_2$/WSe$_2$ heterobilayers

Abstract

Moiré superlattices in heterobilayers of atomically thin transition metal dichalcogenides provide a versatile platform for exploring quantum many-body physics as they can trap excitons, leading to the formation of quantized moiré exciton states. However, such moiré excitons have been predominantly studied at cryogenic temperatures, which severely limits their practical applications. Here, we demonstrate room-temperature activation and control of moiré excitons in MoS$_2$/WSe$_2$ heterobilayers using local strain engineering. Applying mechanical strain with a modified atomic force microscopy tip, we observe a series of resonances attributed to interlayer exciton states confined in the moiré potential. Power-dependent photoluminescence measurements elucidate the population dynamics of the moiré exciton states, while controlled local strain enables continuous tuning of their emission wavelength to the center of the second telecom window. We provide a theoretical model that captures all experimentally observed features, including the unconventional spectral shape of the moiré exciton emission. Our findings establish local tip-induced strain as a powerful tool for the on-demand manipulation of moiré excitons, paving the way for room-temperature quantum excitonic devices.