In this project we will prove the principles of fabricating graphene in a form useful for manufacturing nanoscale electronics and fabricate some simple devices. Graphene is a form of carbon discovered in the 21st century: a single two dimensional sheet of atoms in a hexagonal chickenwire array. It completes the set of carbon materials, which already had zero-dimensional (buckyballs), one-dimensional (nanotubes), and three-dimensional (graphite) members that are all formed by rolling or stacking up graphene sheets. In its simplest form it can be made by anyone / a pencil trace consists of millions of carbon flakes, and amongst the millions a few will be just one atomic sheet thick. Experiments on these flakes have shown that they have really remarkable properties, particularly for electronic components. The two-dimensional nature of the material, along with the symmetry of the lattice, means that the electrons in the graphene sheet have the same dynamics as relativistic particles such neutrinos: they are now commonly referred to as massless Dirac fermions, with a new quantum number, chirality, not possessed by free electrons. This has been shown to lead to bizarre new physics such as finite electrical conductivity without charge carriers and new versions of the quantum Hall effect. Although new nanoelectronic devices based on this novel physics offer exciting possibilities, using graphene can also make marked improvements to present day technologies. This is because it possesses the higher value of a key materials property than any other semiconductor: the mobility. A simple field effect CMOS-like transistor, using a graphene flake to form the channel, outperformed Si by more than a factor of ten. A major obstacle to achieving this is that building complex circuits from randomly placed, shaped, and sized flakes is not possible using today's planar fabrication technologies where reproducibility is key. What is needed a uniform layer of graphene coating an entire wafer that can be patterned and processed in the usual way. The most promising way to do this currently seems to be to use SiC wafers used commercially in high power electronics. A proper surface treatment in ultrahigh vacuum preferentially removes silicon atoms, and the carbon atoms that remain reconstruct themselves to form graphene. The promise of wafer-scale device-grade material offers the possibility of not just forming transistor channels out of graphene, but carving entire circuits from a single graphene sheet. At Leeds we have been working on epitaxial graphene production now for roughly a year. We have set up and tested the various surface science instruments that will be needed to show that graphene has indeed formed on the surface of our SiC wafer. Our recent efforts have concentrated on achieving the very high temperatures for the wafer in UHV that are the key step of producing the surface graphene, and after a series of improvements we are now close to reaching those needed. Once we have graphene, we shall optimize its production and start to make electronic devices from it. In this proof-of-principle project we have two main aims: to develop a reliable protocol for forming graphene on SiC wafers in a form useful for scaling up to manufacturing; and to build some simple demonstrator devices to show that this material can be processed in nanoscale devices including gates that can control a switching action. We will also begin some pilot experiments on connecting magnetic electrodes to graphene devices, with a view to preparing the ground for future projects involving spintronics in graphene/using the electron spin as well as charge to store and process information/which is potentially a very fertile area, as quantum spin states are very long lived in graphene, even at room temperature.

The term 'plasmonics' refers to the science and technology dealing with manipulation of electromagnetic signals by coherent coupling of photons to free electron oscillations at the interface between a conductor and a dielectric. This field of research has emerged as an extremely promising technology with several main fields of application: information technologies, energy, high-density data storage, life sciences and security. The opportunity to guide light in the form of surface plasmon waves on metallic films is attractive for the development of integrated photonic chips where the information can be processed all-optically without the need of electronic-to-optical and optical-to-electronic conversion, as well as for integrating photonics with silicon electronics on a fully compatible platform. Performance of optoelectronic devices, such as light emitting diodes and photodetectors, can also be improved by integrating them with plasmonic nanostructures. Recent research in plasmonics has led to significant progress in development of various passive plasmonic components, such as waveguides, plasmonic crystals, plasmonic metamaterials, with tailored photonic properties. Plasmonic studies have, however, almost exclusively concentrated on pure metallic nanostructures and passive devices with properties fixed by the nanostructure parameters. At the same time, real-life applications require active control to achieve signal switching and modulation, amplification to compensate losses along with the direct generation and detection of plasmons. All these can be realised if plasmonic nanostructures are hybridised with functional (molecular or ferroelectric) materials. Here we propose to develop and study hybrid plasmonic nanostructures consisting of nanostructured metals combined with dielectrics to enable active functionalities in plasmonic circuitry. This project will unlock the plasmonics' potential for improvement of real-world photonic and optoelectronic devices and provide insight into physical phenomena which are important for various areas of optical physics and photonic technologies.

The term 'plasmonics' refers to the science and technology dealing with manipulation of electromagnetic signals by coherent coupling of photons to free electron oscillations at the interface between a conductor and a dielectric. This field of research has emerged as an extremely promising technology with several main fields of application: information technologies, energy, high-density data storage, life sciences and security. The opportunity to guide light in the form of surface plasmon waves on metallic films is attractive for the development of integrated photonic chips where the information can be processed all-optically without the need of electronic-to-optical and optical-to-electronic conversion, as well as for integrating photonics with silicon electronics on a fully compatible platform. Performance of optoelectronic devices, such as light emitting diodes and photodetectors, can also be improved by integrating them with plasmonic nanostructures. Recent research in plasmonics has led to significant progress in development of various passive plasmonic components, such as waveguides, plasmonic crystals, plasmonic metamaterials, with tailored photonic properties. Plasmonic studies have, however, almost exclusively concentrated on pure metallic nanostructures and passive devices with properties fixed by the nanostructure parameters. At the same time, real-life applications require active control to achieve signal switching and modulation, amplification to compensate losses along with the direct generation and detection of plasmons. All these can be realised if plasmonic nanostructures are hybridised with functional (molecular or ferroelectric) materials. Here we propose to develop and study hybrid plasmonic nanostructures consisting of nanostructured metals combined with dielectrics to enable active functionalities in plasmonic circuitry. This project will unlock the plasmonics' potential for improvement of real-world photonic and optoelectronic devices and provide insight into physical phenomena which are important for various areas of optical physics and photonic technologies.

Iron and silicon are two of the most abundant elements in the earth's crust. Nevertheless, the simplest chemical compound of these two elements, iron monosilicide (FeSi), possesses bizarre electronic and magnetic properties that have confounded researchers for decades. At low temperatures it is a non-magnetic semiconductor with a narrow gap. On warming, most materials become harder to magnetise: FeSi becomes easier, and it transforms into a heavy electron metal. Although known experimentally for over four decades, the proper theoretical description of this is still not settled. When cobalt is substituted for iron things get even more interesting. Theory predicts (and indirect experiments on bulk crystals seem to confirm) that each Co atom contributes one current carrying electron, and also one electron spin's worth of magnetism, suggesting a perfectly polarised magnetic semiconductor - and what is more, one based on Si. Indeed, we have recently been able to prepare thin films of this material on commercial silicon wafer that appear to be epilayers: single crystals where every atom is in register with the lattice defined by the substrate. Spin polarisation is the key figure of merit for all spintronic materials, with all spintronic effects growing as the polarisation increases. Having a high polarisation material that is silicon-based is therefore a very tantalising prospect. In the first part of our project we will confirm the nature of our thin films and their structural, magnetic, and electronic properties. We will also investigate a simpler and quicker way of forming films known as sputtering. We will then go on to make the first direct measurements of the spin polarisation of this remarkable material, and moreover, do so in the technologically vital thin film form on Si wafer. The magnetism is truly remarkable in another way, however. The crystal structure of this material is very unusual in that it lacks mirror symmetry, and so an obscure effect that is suppressed in almost every other magnetic material comes into play: the so-called Dzyaloshinskii-Moriya interaction. Instead of the usual uniform state in a ferromagnet, this term causes the spins to spiral around each other in a helix. This can be brought to a uniform saturated state in a large enough magnetic field, but on the way another largely forgotten piece of theoretical physics comes into play. There is an intermediate state formed from a lattice of magnetic vortices called skyrmions, a topological structure first invented to describe fields of pi-mesons in the 1960s. Last year it was shown (using bulk crystals of a related compound, manganese monosilicide) that because of this special topology, these swirling magnetic structures can be set into motion by a current flowing through the crystal at a current density around one million times smaller than that needed to move a vortex in a conventional magnetic material. We shall seek these magnetic skyrmion objects in our silicide wafer samples and measure the current density needed to move them. Unfortunately, this material is only magnetic at temperatures a few tens of degrees above absolute zero, and all magnetic properties are lost well before room temperature is reached. Nevertheless, replacing silicon with its neighbour in the periodic table, germanium, can also transform iron silicide into a helimagnetic metal, with complete replacement preserving this structure up to a temperature a few degrees above zero Celsius. We shall complete our project by doping this material with cobalt and see if the critical temperature can be pushed above room temperature to technologically useful values.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.