Quantum Confining Excitons with an Electrostatic Moiré Superlattice

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Optics

Background:

• Quantum confinement of excitons is crucial for strong exciton interactions and quantum light generation.
• Controlling excitons with nanoscale potentials is challenging compared to electrons.

Purpose of the Study:

• To demonstrate a method for achieving quantum confinement of excitons.
• To investigate the role of electric fields in twisted hexagonal boron nitride (h-BN) on exciton behavior.

Main Methods:

• Utilized piezoelectric force microscopy to image domain structures in twisted h-BN.
• Investigated the optical properties of monolayer MoSe2 placed near twisted h-BN interfaces.

Main Results:

• Observed strong in-plane electric fields at the domain boundaries of twisted h-BN.
• Detected energy splitting of excitons and Fermi polarons at moiré domain boundaries due to nanoscale electrostatic potentials.
• Excitons exhibited pronounced polarization anisotropy, persisting up to ~80 K.

Conclusions:

• The study successfully demonstrated 1D quantum confinement of excitons using twisted h-BN and MoSe2.
• This confinement arises from nanoscale electrostatic potentials at moiré domain boundaries.
• The findings offer new pathways for developing advanced classical and quantum optoelectronic devices.