Large valley polarization in monolayer MoTe₂ on a magnetic substrate

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Valley degree of freedom offers potential for valleytronics.
• Realizing valley polarization requires introducing magnetism into lattices.
• Heterostructures are key for exploring novel electronic properties.

Purpose of the Study:

• To investigate valley polarization in a MoTe2 monolayer on an RbMnCl3 substrate.
• To explore the mechanism of proximity-induced magnetization and valley splitting.
• To understand the interplay between spin-orbit coupling and exchange fields.

Main Methods:

• First principles calculations were employed to simulate the heterostructure.
• An effective Hamiltonian model was used to analyze valley polarization.
• Proximity-induced Zeeman effects were analyzed to understand magnetization.

Main Results:

• A MoTe2 monolayer on RbMnCl3 exhibited significant magnetization due to proximity effects.
• A large valley splitting of approximately 109 meV was achieved.
• Valley splitting magnitude is limited by spin-orbit coupling and exchange field.

Conclusions:

• The MoTe2/RbMnCl3 heterostructure effectively induces valley polarization.
• Understanding the competition between SOC and exchange fields is crucial for enhancing valley polarization.
• A device concept for an anomalous valley Hall effect was proposed.