Distinctive g-factor of moire-confined excitons in van der Waals heterostructures

TL;DR

This study reveals that moire patterns in van der Waals heterostructures cause a distinctive g-factor in excitons, highlighting the role of exciton confinement in magnetic response and advancing understanding of moire effects.

Contribution

It provides experimental evidence linking moire-induced exciton confinement to unique g-factors in heterostructures, a novel insight into excitonic behavior in these materials.

Findings

Reduced g-factor for lower energy exciton peak

Evidence of exciton confinement due to moire pattern

Magneto-PL as a tool to study moire effects

Abstract

We investigated experimentally the valley Zeeman splitting of excitonic peaks in the photoluminescence (PL) spectra of high-quality hBN/WS2/MoSe2/hBN heterostructures at near-zero twist angles under perpendicular magnetic fields up to 20 T. We identify two neutral exciton peaks in the PL spectra: the lower energy one exhibits a reduced g-factor relative to that of the higher energy peak, and much lower than the recently reported values for interlayer excitons in other van der Waals (vdW) heterostructures. We provide evidence that such a discernible g-factor stems from the spatial confinement of the exciton in the potential landscape created by the moire pattern, due tolattice mismatch and/or inter-layer twist in heterobilayers. This renders magneto-PL an important tool to reach deeper understanding of the effect of moire patterns on excitonic confinement in vdW heterostructures.