Department of PhysicsJohn Anderson Research Colloquia

Coordinated with the Colloquia at the Department of Physics and Astronomy of the University of Glasgow. (They may have donuts but we have free chocolate covered biscuits and coffee!)

Colloquia Schedule 2025-2026

* Note: Outside of regular schedule.

Steven Jamison (Lancaster University) 22nd October 2025, JA 314

Femtosecond duration electron bunches are highly sought after, finding application in areas such as ultrafast electron diffraction and microscopy, and in the generation of intense x-ray sources in free-electron lasers. Here I will present an overview of the Terahertz-acceleration research programme in the Cockcroft institute, where we  are developing the concepts and technology for creating of such ultrafast electron beams using laser-generated THz pulses. This relatively new approach to control and accelerate electron beams - only a decade in the development – is receiving growing attention for its ability to compress, deflect and accelerate ultrashort electron bunches, and to enforce a femtosecond-level temporal locking of electrons to a secondary laser source.
The concepts of THz acceleration bring together a diverse range of physics. I will discuss high-power, high-field THz generation from spintronic emitters; from non-linear difference frequency mixing; and large area current-surge photoconductive antenna. As an example, we have generated quasi-monochromatic THz pulses in excess of 100 uJ of THz from ‘home-built’ periodic-poled nonlinear-optical structures. The generation of THz vector beams, with electric field polarisation parallel to the electromagnetic propagation direction is also required, to enable electro-magnetic energy exchange with co-propagating electron bunches. In an analogue of optical phase-matching, the electro-magnetic pulse is also slowed (and confined) in sub-mm dielectric and metallic structures, providing phase-matching to the electron velocity (with electron velocities from 0.5c to 0.99998c).
Examples discussed will range from sub-relativistic 100 keV electron beams, through to 230 MeV fully relativistic beams. The presentation will complete the tour with recent results showing how THz-temporal locking can enable a hybrid radio-frequency and plasma accelerator, solving several-decade standing problems inhibiting ‘external injection’ of electron beams into a plasma accelerator.  Such an external injection concept holds potential for delivering high-quality and stability to GeV electron beams from compact plasma accelerators.

Keith McKenna (University of York) 5th November 2025, JA 3.14

Optimising the performance of polycrystalline semiconductors for many applications in technology requires understanding how extended defects affect their electronic properties. In this talk I will introduce approaches to predictively model extended defects using density functional theory and highlight how they can be combined with scanning transmission electron microscopy to provide deep understanding of complex defects at the atomic scale [1]. I will present several examples from our recent research with a focus on materials with applications in photovoltaics. These will include anatase TiO2 (widely employed as an electron transport layer) [2,3], Sb2Se3 (an emerging thin-film solar absorber with an apparent intrinsic tolerance to extended defects) [4,5] and pnictogen chalcohalides (a wider class of promising materials which we have also recently found to be tolerant to extended defects). I will conclude with a summary of some of the challenges and opportunities for future research.

 

References:

[1] J. Quirk et al, Appl. Phys. Rev. 11, 011308 (2024)

[2] J. Quirk et al, Adv. Theory Simul. 2, 1900157 (2019)

[3] J. Quirk et al, Nano Lett. 21, 9217 (2021)

[4] K. P. McKenna, Adv. Electron. Mater. 7, 2000908 (2021)

[5] R. A. Lomas-Zapata et al, Phys. Rev. X Energy 3, 013006 (2024)

Grayson Noah (Quantum Motion Ltd) 19th November 2025, JA 314

Silicon spin-based quantum computing has seen substantial progress in the last few years - developments include demonstrations of fidelities above the fault-tolerant threshold and scaling to several-qubit devices, including Quantum Motion's deployment of the first full-stack silicon MOS quantum computer at the UK's National Quantum Computing Centre (NQCC). The development of advanced cryo-electronics and the unique integration opportunities offered by cryo-CMOS hold the keys to unlocking scalable architectures to support utility-scale fault-tolerant quantum computing. We present Quantum Motion's recent work in industrially fabricated cryo-CMOS electronics and qubits, scalable approaches to readout, and thermal characterisation and modelling.

Jack Donoghue (Henry Royce Institute, Department of Materials, University of Manchester) 3rd December 2025, JA 314

Electron backscatter diffraction (EBSD) is an analytical technique used in scanning electron microscopes to study the crystallographic structure of materials. EBSD can be used to map the orientation of crystals to a very high angular resolution (<0.1° orientation resolution), at a high spatial resolution (typically <50nm), and can also be used to identify and distinguish different crystal structures where there are several present in a sample. The first commercial EBSD systems became available in the early nineteen nineties and it has become an established technique in a number of fields including geology, materials science, and semiconductor research. However, EBSD technology development continues to be rapid, and as the technology becomes more capable so the applications broaden to include things such as life sciences and in situ studies.
In this colloquium I will give a quick introduction to EBSD covering the generation of electron backscatter diffraction patterns (EBSPs), how we collect them, what information we can extract from them, and what this means for the studies that use the technique. I will be speaking largely from a materials science standpoint (specifically metallurgy) but the concepts are applicable to any crystallographic material. I will finish with an overview of more advanced EBSD techniques that we have spent the last few years developing at the University of Manchester including 3D EBSD through serial sectioning, and in situ studies where we carry out EBSD while the sample is exposed to temperature and/or strain.

Silvia Cipiccia (UCL) 11th February 2026, JA 314

TBA

Robert Cameron (University of Strathclyde) 25th March 2026, JA 314

TBA