Probing Dielectric Screening in van der Waals Heterostructures via Pressure-Tuned Exciton Rydberg Series

TL;DR

This paper demonstrates a method to probe dielectric changes in van der Waals heterostructures by analyzing pressure-induced shifts in exciton Rydberg series in monolayer WSe2 encapsulated in hBN.

Contribution

It introduces a novel pressure-tuned excitonic spectroscopy technique to measure dielectric properties of hBN in van der Waals heterostructures.

Findings

Pressure modifies the dielectric environment of excitons.

The Rydberg series shifts reveal changes in dielectric constant.

The method enables direct dielectric sensing under pressure.

Abstract

Excitons in two-dimensional semiconductors are directly exposed to the environment and are sensitive to the dielectric properties of their surrounding. Here, we show that the Rydberg series of excited states of excitons in a monolayer WSe$_2$ encapsulated in hexagonal boron nitride (hBN) can be used to probe the pressure-induced modifications of the surrounding dielectric properties. We propose a model based on the pressure induced evolution of the interlayer distances in this van der Waals heterostructure and on the bulk dielectric properties of hBN. This approach allows a direct measurement of the dielectric constant of pressurized hBN and establishes a new methodology for dielectric sensing.