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Proceedings Paper

Electrical control of opto-valleytronic spin and charge injections in monolayer MoS2/graphene hybrid van der Waals systems (Conference Presentation)
Author(s): Yunqiu Kelly Luo

Paper Abstract

The goal of our research is to establish the feasibility of the information transduction between electronic, spintronic, and photonic states in 2D hybrid systems. Our initial work demonstrated, for the first time, the efficient optical manipulation of spin polarization in a MoS2/graphene heterostructure. We observed that the magnitude and direction of spin polarization can be controlled by photon helicity and photon energy. In addition, we achieved the full functionality at room temperature, which is invaluable for the technological prospects of 2D materials. Currently, we are studying the underlying mechanisms of photon-to-spin and photon-to-charge conversions at 2D heterostructure interface. Experimentally, we implement dual-gated electrostatic manipulation of optical spin and charge transfer across monolayer MoS2/monolayer graphene interface, which will give us insights into the band alignment and tunability between the two materials. Theoretically, our DFT and analytic theory co-workers model the diffusion of optically excited spin and charge at the interface, as well as investigate the role of spin orbit coupling on the spin transfer process. Our initial findings reveal an intriguing bias enhancement of photoconductivity at MoS2/graphene interface, which behaves oppositely across graphene charge neutrality point. Doping dependence and photon intensity dependence indicate strongly towards the dominance of graphene photothermoelectric effect for below MoS2 gap excitation, while an interplay of MoS2 photoelectric effect and graphene photothermoelectric effect mediates above gap excitation. Our results establish the scientific foundation of photon-to-spin and photon-to-charge transduction in 2D hybrid systems, and thereby enable significant advance for future nanoscale ultra-low-power information processors.

Paper Details

Date Published: 10 September 2019
Proc. SPIE 11090, Spintronics XII, 110902G (10 September 2019); doi: 10.1117/12.2527721
Show Author Affiliations
Yunqiu Kelly Luo, The Ohio State Univ. (United States)

Published in SPIE Proceedings Vol. 11090:
Spintronics XII
Henri-Jean M. Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi, Editor(s)

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