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Optoelectrically controlled transistors in graphene-based valley-gapless, indirect-gap, and spin-valley-gapless
Xiao-Long Lü1, Ze-Han Hu1, Xin-Zhi Liu1
1College of Science, Guangxi University of Science and Technology, Liuzhou, Guangxi 545006, China.
Iscience
|June 17, 2026
Summary
We demonstrate optically controlled graphene semiconductors for tunable spin-polarized currents. This enables novel optoelectrically controlled transistors for spintronics and valleytronics applications.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Information Science
Background:
- Spintronics, valleytronics, and spin-valleytronics rely on controlling spin and valley polarized currents.
- Graphene-based semiconductors offer a promising platform for advanced electronic devices.
Purpose of the Study:
- To propose and investigate optically controlled graphene-based multi-gapless semiconductors.
- To enable electrical modulation of spin-, valley-, and spin-valley-polarized currents.
Main Methods:
- Utilizing antiferromagnetic exchange fields and a modified Haldane model to induce gapless semiconductor states.
- Applying off-resonant circularly polarized light to tune semiconductor properties.
- Modulating gate voltage and optical intensity to control spin and valley degrees of freedom.
Main Results:
- Valley-gapless semiconductors transition to spin-valley-gapless semiconductors under light.
- Gapless semiconductors switch to indirect-gap semiconductors with increasing optical intensity.
- Optically modulated semiconductors yield fully spin-polarized, spin-valley-polarized currents, or an 'off' state.
Conclusions:
- Demonstrated optoelectrically controlled transistors using gapless semiconductors.
- Highlighted the potential of these materials for advanced valleytronic and spin-valleytronic devices.
- Showcased the tunability of spin and valley properties via gate voltage and optical control.
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