Charge, spin and heat transport in graphene field effect transistors

Information coded in the magnetisation direction of tiny nanomagnets is the basis of modern hard disk drives (HDD) which is crucial for the present-day information technology revolution. Reading or writing data from HDD involves switching the magnetisation direction of nanomagnetic bits using electrical currents. However, one of the main challenges in such devices remains the large production of unwanted heat (Joule heating) associated with the flow of electrons.

One of the promising routes toward novel and low-power electronic devices is using the 'dissipationless' flow of electron spin angular momentum or spin currents, enabling spin logic circuits and computing devices. It is, therefore, crucial to develop efficient ways of creating, transporting, manipulating, and detecting spins over long distances.

In this talk, I will show how spin currents are generated in a simple spin valve device and explain how materials engineering is paving the way for better spintronic proof-of-concept devices and spin field-effect transistors. Using graphene, an atomically thin two-dimensional material with exotic spintronic properties, as a spin transport channel, I will show how spins can be transported over long distances without losing spin information and how we can control this distance by changing the number of layers of graphene. In addition, I will discuss radically new device concepts that utilise waste heat generated by other computing tasks for reading and writing information to hard disk drives.