# Spin-layer locking of interlayer excitons trapped in moir\'e potentials

## TL;DR

This paper reports the discovery of spin-layer locking in interlayer excitons within moiré potentials in TMD heterostructures, revealing new quantum degrees of freedom for engineering tunable quantum systems.

## Contribution

It demonstrates spin-layer locking of interlayer excitons in moiré potentials, highlighting the intrinsic locking of atomic registries in 2H-stacked TMD heterostructures.

## Key findings

- Observation of spin-layer locking in interlayer excitons
- Identification of two quantum-confined exciton species with distinct configurations
- Intrinsic locking of moiré site registries due to 2H stacking

## Abstract

Van der Waals heterostructures offer attractive opportunities to design quantum materials. For instance, transition metal dichalcogenides (TMDs) possess three quantum degrees of freedom: spin, valley index, and layer index. Further, twisted TMD heterobilayers can form moir\'e patterns that modulate the electronic band structure according to atomic registry, leading to spatial confinement of interlayer exciton (IXs). Here we report the observation of spin-layer locking of IXs trapped in moir\'e potentials formed in a heterostructure of bilayer 2H-MoSe$_2$ and monolayer WSe$_2$. The phenomenon of locked electron spin and layer index leads to two quantum-confined IX species with distinct spin-layer-valley configurations. Furthermore, we observe that the atomic registries of the moir\'e trapping sites in the three layers are intrinsically locked together due to the 2H-type stacking characteristic of bilayer TMDs. These results identify the layer index as a useful degree of freedom to engineer tunable few-level quantum systems in two-dimensional heterostructures.