Sergio O. Valenzuela: Spin and Hot-Carrier Transport in Graphene-Based Devices
Graphene has great potential as a building block for new spintronic applications. Room temperature spin relaxation lengths of over 30 micrometers have been achieved. The combination of spin transport with spin manipulation, by inducing magnetic correlations or large spin-orbit coupling by proximity with suitable materials, may pave the way to disruptive spintronic technologies based on "all-graphene" devices. In this talk I will start by describing our understanding of the basic spin relaxation mechanisms in graphene, which are the key to achieve full control of the spin degree of freedom. I will introduce the main theoretical models and discuss our recent efforts aiming at highlighting their peculiarities; in particular, at verifying whether the spin relaxation is anisotropic, which would be the hallmark of a dominant spin orbit field. Then, I will introduce 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. In addition, I will present evidence that the spin propagation can be reinforced (suppressed) by the presence of hot electrons, suggesting that the remote spin accumulation can be controlled using temperature gradients.