Optical Injection and Detection of Long-Lived Interlayer Excitons in van der Waals Heterostructures

TL;DR

This paper presents an optical method to generate and measure long-lived interlayer excitons in van der Waals heterostructures, enabling new studies of correlated bosonic phases with high resolution.

Contribution

It introduces a novel optical technique for creating and characterizing long-lived interlayer excitons, with lifetimes up to 8.8 microseconds, increasing with hBN thickness.

Findings

Confirmed presence of tightly bound interlayer excitons via 1s and 2s intralayer measurements

Achieved interlayer exciton lifetimes up to 8.8 microseconds

Demonstrated potential for exploring Bose-Fermi mixtures with high spatial and temporal resolution

Abstract

Interlayer excitons in semiconducting bilayers separated by insulating hBN layers constitute a promising platform for investigation of strongly correlated bosonic phases. Here, we report an optical method for the generation and characterization of long-lived interlayer excitons. We confirm the presence of tightly bound interlayer excitons by measuring 1s and 2s intralayer excitons in each layer concurrently. Using a pump-probe technique, we find interlayer exciton lifetimes up to 8.8 $\mu$s, increasing with the thickness of the hBN. With optical access to long-lived interlayer excitons, our approach provides a new route to explore degenerate Bose--Fermi mixtures of excitons and itinerant electrons with high spatial and temporal resolution.