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Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures
Published on: December 5, 2015
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Negative valley polarization in doped monolayer MoSe2
Yueh-Chun Wu1, Takashi Taniguchi2, Kenji Watanabe3
1Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA. yan@physics.umass.edu.
Physical Chemistry Chemical Physics : PCCP
|December 8, 2021
Summary
Charge doping and magnetic fields enable effective control of valley polarization in monolayer molybdenum diselenide (1L-MoSe2). This allows tuning polarization to negative values, a novel finding for this material.
Area of Science:
- Condensed matter physics
- Materials science
- 2D materials
Background:
- Monolayer molybdenum diselenide (1L-MoSe2) is a transition metal dichalcogenide with inefficient optical valley polarization.
- Controlling valley polarization is crucial for spintronic and valleytronic applications.
Purpose of the Study:
- To investigate methods for effectively controlling valley polarization in 1L-MoSe2.
- To explore the possibility of achieving negative valley polarization values.
Main Methods:
- Utilizing charge doping via gate-induced methods.
- Applying an external magnetic field.
- Optical spectroscopy to measure valley polarization.
Main Results:
- Demonstrated effective control of valley polarization in 1L-MoSe2 through combined charge doping and magnetic field.
- Achieved tunable negative values for valley polarization.
- Observed that the higher energy Zeeman mode emission is more intense than the lower energy one in negative polarization states.
Conclusions:
- Valley-selective exciton-charge dressing explains the observed phenomena.
- Gate-induced doping, in the presence of Zeeman splitting, populates specific valleys, enabling polarization control.
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