Publication News

Page 1 of 10  > >>

 

7th August 2017

Valley-addressable polaritons in atomically thin semiconductors

Dr Aurélien Trichet and Prof Jason Smith in the Photonic Nanomaterials Group have recently published their latest work on cavity QED with 2D materials in Nature Photonics. In this work, the formation of polariton states in cavity-coupled monolayer MoSe2 allows the observation of spin-valley effects that were previously invisible in this material. The work is in collaboration with the Tartakovskii group at the University of Sheffield, the Novoselov group at the University of Manchester, and the Malpuech group at the Institut Pascal. A News and Views article discussing the work has also been published.

phasechange photonic memory

4th August 2017

Phase-change materials for non-volatile photonic applications

Professor Harish Bhaskaran and co-authors recently published an invited review paper in Nature Photonics covering the newly emerging area of phase change photonics. Matthias Wuttig at RWTH Aachen is the world's leading expert on the materials science of these materials; Harish Bhaskaran covered their use in applications such as displays and emerging photonic memory and cognitive computing applications; Thomas Taubner covered their use in reconfigurable nanophotonics (metamaterials).

 

3rd August 2017

Dislocation loop evolution during in-situ ion irradiation of model FeCrAl alloys

Jack Haley in the MFFP Group reports in Acta Materialia an investigation into how radiation damage accumulates in FeCrAl alloys by irradiating a selection of alloys in-situ with Transmission Electron Microscopy (TEM). FeCrAl alloys are candidates for fuel cladding in Pressurised Water Reactors that can exhibit enhanced accident tolerance compared with the zirconium based alloys in use today.

 

1st August 2017

Scaling Limits of Graphene Nanoelectrodes

Syed Ghazi in collaboration with Jan Mol recently published in NanoLetters the first report of the fact that scaling of graphene nanoelectrodes has a limit imposed by the formation and breaking of carbon bonds when the gaps sizes are below a few nm. This builds upon years of work in scaling down electrode limits and shows our data which suggests (completely unexpectedly) that there is a limit to scaling.

 

27th July 2017

Mixed-Mode Electro-Optical Operation of Ge2Sb2Te5 Nanoscale Crossbar Devices, Advanced Electronic Materials

This report in Advanced Electronic Materials by Gerardo Rodriguez‐Hernandez in the NanoEng group shows the operation of phase change devices in the mixed optical and electrical domain, and builds a non-volatile mixed-mode switch. It shows that the actual design of the optical stack determines absorption, which can thus be tuned depending on the wavelength.

 

16th June 2017

LiO2: Cryosynthesis and Chemical/Electrochemical Reactivities

Researchers from the Peter Bruce Group have recently studied the synthesis and chemical/electrochemical reactivities of LiO2 species in liquid NH3 and compared its chemical reactivity with those of O2-. The paper in J. Phys. Chem. Lett. reports that O2- and Li2O2 are stable in liquid NH3, while LiO2 can react with liquid NH3 forming LiOH and LiOH.H2O, suggesting it is the most reactive oxygen species in Li-O2 batteries.

16th June 2017

Phenol-Catalyzed Discharge in the Aprotic Lithium-Oxygen Battery

Discharge in the lithium-O2 battery is known to occur either by a solution mechanism, which enables high capacity and rates, or a surface mechanism, which passivates the electrode surface and limits performance. Researchers from the Peter Bruce Group have recently reported in Angewandte Chemie that the introduction of the protic additive phenol to ethers can promote a solution phase discharge mechanism. Phenol acts as a phase-transfer catalyst, dissolving the product Li2O2, avoiding electrode passivation and forming large particles of Li2O2 product; vital requirements for high performance.

Polaron to Fermi Liquid Transition

9th June 2017

Origin of the crossover from polarons to Fermi liquids in transition metal oxides

Understanding the nature of charge carriers in doped oxides is key to engineer the conduction properties of these materials. Angle-resolved photoemission spectroscopy experiments on prototypical metal oxides have shown that the carriers undergo a transition from a polaronic to a Fermi liquid regime with increasing doping. In a paper published in the journal Nature Communications, Carla Verdi, Fabio Caruso and Feliciano Giustino investigate this problem by performing first principles many-body calculations of angle-resolved photoemission spectra of doped anatase TiO
2. They show that this transition is driven by nonadiabatic Fröhlich electron-phonon coupling, and occurs when the frequency scale of plasma oscillations is of the same order as that of longitudinal-optical phonons in the material.

Interferogram - experimental versus theoretical

17th May 2017

Direct Measurement of the Surface Energy of Graphene

A recent publication in Nano Letters reports the successful application of the graphene surface force balance (g-SFB) to directly measure the surface energy of pure graphene. Access to accurate surface energy values of graphene is not only of fundamental interest, but provides a useful reference for anyone involved in research on graphene properties, (surface) modifications, and the implementation of graphene in devices.  

This work is the result of a close collaboration between the Nanomaterials by Design Team lead by Professor Grobert in the Department of Materials and the Surface Forces Research Laboratory led by Prof Susan Perkin in the Department of Chemistry over many years and many years of fine tuning large-area graphene synthesis and transfer in conjunction with an in-depth understanding and fundamental development of the surface-force-balance technique.  The work has been made possible largely through ERC funding.  This publication was also selected as a research highlight in Nanowerk.

Electron spin dephasing

2nd May 2017

Hyperfine and Spin-Orbit Coupling Effects on Decay of Spin-Valley States in a Carbon Nanotube

The two spin states of an electron provide a natural qubit that can be used the basis of a semiconductor quantum computer or as a sensitive probe of device physics on the nanoscale. However, quantum superpositions of the two spin states are delicate and easily destroyed by uncontrolled interactions with the environment. In a new paper in Physical Review Letters, Tian Pei and colleagues have identified the mechanisms that degrade the quantum states of electron spins in a carbon nanotube. Using nanotechnology to fabricate traps for electrons along the nanotube and measuring at ultra-low temperatures well below 1 kelvin, they are able to distinguish the effects of hyperfine coupling and spin-orbit interaction on the spin states. In this device, they find that hyperfine coupling is the main source of spin dephasing, but this effect can be eliminated in future experiments by specially preparing nanotubes that are free of magnetic nuclei. This work is in collaboration with Budapest University of Technology and Economics and uses low-temperature measurement facilities in our recently expanded Ferreras Willetts Laboratory.

Page 1 of 10  > >>