Light-Induced Electron Pairing in a Bilayer Structure

TL;DR

This paper provides experimental evidence for charged bosonic states in bilayer TMDs, highlighting their potential for Bose-Einstein condensation and superconductivity through electrostatic and magnetic measurements.

Contribution

It confirms the existence of doubly charged exciton states as charged bosons in bilayer TMDs using electrostatic and magnetic measurements, advancing understanding of their quantum properties.

Findings

Control of doping density affects population of charged bosons.

Magnetic field dependence shows the bound state is a spin triplet.

Results suggest potential for BEC and superconductivity in the system.

Abstract

Previous experimental and theoretical work has given evidence of the existence of doubly charged exciton states in strongly screened bilayers of transition metal dichalcogenide (TMD) layers. These complexes are important because they are performed electron pairs that can, in principle, undergo Bose-Einstein condensation (BEC), in which case they would also form a new type of superconductor, consisting of stable bosons with net charges. In this paper, we present key electrostatic and magnetic measurements that definitively confirm the existence of these charged bosons. These measurements include 1) continuous control of the doping density with both positive and negative carriers, showing the expected population dependencies on the free carrier density, and 2) measurement of the dependence on the magnetic field, showing that this new bound state is a spin triplet. These results imply that it is promising to look for BEC and superconductivity in this system.