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26 November 2018

Spin and Hot Carrier Transport in Graphene

Title: Spin and Hot Carrier Transport in Graphene.
When: Thursday, November 29, (2018), 12:00.
Place: Department of Condensed Matter Physics, Faculty of Sciences, Module 3, Seminar Room (5th Floor).
Speaker: Juan F. Sierra, Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and the Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.

In recent years, spintronic technologies, in which information is carried by spin instead of charge, have become a promising candidate for “beyond-CMOS” devices. Graphene and other two-dimensional materials have rapidly established themselves as intriguing building blocks for spintronic applications [1]. Owing to graphene intrinsic low spin-orbit interaction, spins can flow snugly through its crystal lattice over long distances resulting in an ideal spin channel but, at the same time, making it difficult to manipulate spins, which is the cornerstone for successfully implementing spin-based devices. In this talk I will first present a series of experiments where we study spin transport and relaxation mechanisms in graphene spin valve devices and in graphene/transition-metal dichalcogenide heterostructures [2]. In the latter case, I will show how modification of the graphene spin-orbit interaction by proximity effect results in anisotropic spin dynamics and how this finding is relevant for spin-gate engineering [3]. In the second part of the talk, I will discuss the generation, propagation and detection of hot carriers in graphene using purely electrical means. I will show that because typical carrier cooling times can be similar to spin lifetimes, it is possible to implement nonlocal hot-carrier injection and detection methods analogous to those used for spin [4]. In addition, I will present evidence that the spin propagation can be reinforced by the presence of hot carriers [5].

References

1. W. Han et al Nature Nanotechnology 9, 794 (2014)
2. B. Raes, et al. Nature Communications 7, 11444 (2016).
3. L. A. Benítez, J. F. Sierra et al. Nature Physics 14, 303 (2018)
4. J. F. Sierra et al., Nano Letters. 15, 4000 (2015)
5. J. F. Sierra et al., Nature Nanotechnology 13, 107 (2018)

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