Intrinsic Localized Excitons in MoSe₂/CrSBr Heterostructure.

Area of Science:

• Condensed Matter Physics
• Materials Science
• 2D Materials

Background:

• Excitonic properties in 2D semiconductor-magnet heterostructures are not fully understood.
• Magnetic proximity effects are extensively studied but lack fundamental excitonic insights.

Purpose of the Study:

• To investigate the elusive excitonic properties of 2D semiconductor-magnet heterostructures.
• To unveil the origin and behavior of localized excitons in MoSe2/CrSBr heterostructures.

Main Methods:

• Photoluminescence spectroscopy to identify new emission features (X*).
• Magnetic field-dependent measurements to study valley polarization.
• Density Functional Theory (DFT) calculations for band alignment analysis.

Main Results:

• A novel localized exciton emission (X*) was observed in MoSe2/CrSBr heterostructures.
• X* excitons are confined by intrinsic defects within the CrSBr layer.
• Opposite valley polarization polarities for X* and trions under magnetic fields were found, correlating with CrSBr magnetic order.
• Spin-dependent charge transfer and type-II band alignment were identified.
• In-plane anisotropy of CrSBr leads to unique polarization-dependent MoSe2 emissions.

Conclusions:

• Intrinsic defects play a critical role in defining excitonic properties in van der Waals heterostructures.
• This study provides insights into spectrally resolved proximity effects in 2D semiconductor-magnet systems.
• The findings pave the way for novel spintronic and optoelectronic applications leveraging defect-engineered heterostructures.