Optospintronics in graphene via proximity coupling
arXiv:1705.10267 · doi:10.1021/acsnano.7b06800
Abstract
The observation of micron size spin relaxation makes graphene a promising material for applications in spintronics requiring long distance spin communication. However, spin dependent scatterings at the contact/graphene interfaces affect the spin injection efficiencies and hence prevent the material from achieving its full potential. While this major issue could be eliminated by nondestructive direct optical spin injection schemes, graphenes intrinsically low spin orbit coupling strength and optical absorption place an obstacle in their realization. We overcome this challenge by creating sharp artificial interfaces between graphene and WSe2 monolayers. Application of a circularly polarized light activates the spin polarized charge carriers in the WSe2 layer due to its spin coupled valley selective absorption. These carriers diffuse into the superjacent graphene layer, transport over a 3.5 um distance, and are finally detected electrically using BN/Co contacts in a non local geometry. Polarization dependent measurements confirm the spin origin of the non local signal.
References in corpus (12)
- Valley polarization in MoS2 monolayers by optical pumping
- Micrometer-scale ballistic transport in encapsulated graphene at room temperature
- Graphene Spintronics
- Measurement of the optical dielectric function of transition metal dichalcogenide monolayers: MoS2, MoSe2, WS2 and WSe2
- Spin qubits in graphene quantum dots
- Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
- Tunneling Spin Injection into Single Layer Graphene (Supplementary Information)
- Tunneling Spin Injection into Single Layer Graphene
- Opto-Valleytronic Spin Injection in Monolayer MoS2/Few-Layer Graphene Hybrid Spin Valves
- Valley Polarization by Spin Injection in a Light-Emitting van der Waals Heterojunction
- Gate-tunable black phosphorus spin valve with nanosecond spin lifetimes
- All-optical injection of charge, spin and valley currents in monolayer transition metal dichalcogenides