Giant Valley Zeeman Splitting in Vanadium-Doped WSe₂ Monolayers

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Two-dimensional (2D) dilute magnetic semiconductors (DMS) based on transition metal dichalcogenides (TMDs) are promising for spintronic technologies.
• The influence of magnetic ordering on valley degeneracy and optical transition g-factors in these materials is not well understood.

Purpose of the Study:

• Investigate the impact of magnetic ordering on valley degeneracy and optical transition g-factors in vanadium-doped WSe2 monolayers.
• Explore the potential of defect engineering in 2D materials for spintronic applications.

Main Methods:

• Magneto-photoluminescence (PL) experiments at 4 K and room temperature.
• Ab initio calculations for electronic structure and magnetic ordering.
• Phenomenological analysis to correlate experimental and theoretical findings.

Main Results:

• Observed giant effective g-factors (≈-27 to -69) for bound excitons in vanadium-doped WSe2 monolayers at 4 K.
• The giant g-factor diminished at room temperature, indicating a link to low-temperature magnetic ordering.
• Ab initio calculations confirmed magnetic ordering of vanadium states, causing valence band degeneracy breaking at K and K' points.

Conclusions:

• Magnetic ordering of vanadium impurities in 2D WSe2 is responsible for the giant effective g-factor and valence band splitting.
• Defect engineering of 2D materials offers a viable route for developing advanced spintronic devices.