# Many-Body Effect of Mesoscopic Localized States in MoS$_2$ Monolayer

## TL;DR

This paper investigates mesoscopic localized states in MoS$_2$ monolayers, revealing many-body effects, fine structure splitting, magnetic field responses, and diamagnetism, highlighting their potential in quantum photonics.

## Contribution

It demonstrates the existence and properties of mesoscopic localized states in MoS$_2$ monolayers, a new class of many-body quantum systems with unique optical and magnetic behaviors.

## Key findings

- Observation of fine structure splitting similar to quantum dots
- Magnetic field induces polarization changes in localized states
- Large quadratic diamagnetism observed at mesoscopic scale

## Abstract

Transition metal dichalcogenide monolayers provide an emerging material system to implement quantum photonics with intrinsic two-dimensional excitons or embedded zero-dimensional localized states. Here we demonstrate the mesoscopic localized states between two- and zero- dimensions, which is a many-body system with electron-electron Coulomb interactions. A fine structure splitting is observed, which is similar to quantum dots. Meanwhile the polarization is changed by the magnetic field, due to the nature of two-dimensional monolayers. Furthermore, a large quadratic diamagnetism with a coefficient of around $100\ \mathrm{\mu eV/T^2}$ is observed, as a unique consequence of the mesoscopic scale. The many-body effect also results in the emission energy variation and linewidth narrowing in the spectrum, which corresponds well to the theoretical analysis. These unique properties indicate the great potential of mesoscopic localized states in many-body physics and quantum photonics.