Spin-Selective Hole-Exciton Coupling in a V-Doped WSe₂ Ferromagnetic Semiconductor at Room Temperature

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• Two-dimensional (2D) transition metal dichalcogenides (TMDs) show valley polarization and Zeeman splitting under magnetic fields.
• Incorporating magnetic dopants enhances Zeeman splitting in TMDs.
• Vanadium (V) doping offers room-temperature ferromagnetism and significant band edge shifting in semiconductors.

Purpose of the Study:

• Investigate exciton interactions with spin-polarized carriers in V-doped TMDs.
• Report anomalous circularly polarized photoluminescence (CPL) in V-doped WSe2 monolayer.
• Elucidate the origin of excitons and trions in V-doped WSe2.

Main Methods:

• Circularly polarized photoluminescence (CPL) spectroscopy at room temperature.
• Transient absorption spectroscopy.
• Ferromagnetic characterization via Zeeman splitting of nanodiamonds.

Main Results:

• Observed anomalous CPL in V-doped WSe2 monolayer at room temperature.
• Excitons couple with V-induced spin-polarized holes, forming spin-selective positive trions.
• Distinguished between defect-mediated and impurity-mediated trions.
• Confirmed ferromagnetic properties through Zeeman splitting of nanodiamonds.

Conclusions:

• V-doped WSe2 exhibits unique exciton-trion dynamics and room-temperature ferromagnetism.
• The study provides insights into spin-polarized carrier interactions in magnetic 2D semiconductors.
• Anomalous CPL and distinct trion origins are key findings for V-doped TMDs.