Electrically switchable valley polarization, spin/valley filter, and valve effects in transition-metal dichalcogenide monolayers interfaced with two-dimensional ferromagnetic semiconductors

Abstract

Electron valleys in transition-metal dichalcogenide monolayers drive novel physics and allow designing multifunctional architectures for applications. We propose to manipulate the electron valleys in these systems for spin/valley filter and valve devices through band engineering. Instead of the magnetic proximity effect that has been extensively used in previous studies, in our strategy, the electron valleys are directly coupled to the spin-polarized states of the two-dimensional ferromagnets. We find that this coupling results in a valley-selective gap opening due to the spin-momentum locking in the transition-metal dichalcogenide monolayers. This physics gives rise to a variety of unexpected electronic properties and phenomena including halfmetallicity, electrically switchable valley polarization, spin/valley filter and valve effects in the transition-metal dichalcogenide monolayers. We further demonstrate our idea in MoTe${}_2$/CoCl${}_2$ and CoCl${}_2$/MoTe${}_2$/CoCl${}_2$ van der Waals heterojunctions based on first-principles calculations. Thus, our study provides a way of engineering the electron valleys in transition-metal dichalcogenide monolayers for new-concept devices.

6 pages, 4 figures

References in corpus (8)

• Valley polarization in MoS2 monolayers by optical pumping
• The Valley Hall Effect in MoS2 Transistors
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
• Breaking of valley degeneracy by magnetic field in monolayer MoSe2
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Electronic structure and magnetism of transition metal dihalides: bulk to monolayer
• Large valley splitting in monolayer WS${}_2$ by proximity coupling to an insulating antiferromagnetic substrate

Cited by in corpus (5)

• Enforced symmetry breaking for anomalous valley Hall effect in two-dimensional hexagonal lattices
• Strong magnetic proximity effect in Van der Waals heterostructures driven by direct hybridization
• Momentum matching and band-alignment type in van der Waals heterostructures: Interfacial effects and materials screening
• Electric field controlled valley-polarized photocurrent switch based on the circular bulk photovoltaic effect
• Ultrafast Saddletronics